captioning sponsored by newshour productions, llc >> woodruff: good evening. i'm judy woodruff. gwen ifill is on assignment. on the newshour tonight: the tightening presidential race. we break down the latest poll numbers and delve into where the candidates stand on the issue of climate change. then, as chicago mourns its 500th homicide in this year alone, residents desperately search for solutions to the rise in gun violence. >> it's going to take a lot of people all doing something-- not saying something, but doing something-- to fix the problem. >> woodruff: and, 15 years after 9/11, a new battlefront for fighting terrorism. how much responsibility do social media networks have towo stop the spread of extremism online?

>> it seems appealing to say, "oh, just have the major social media companies take a hard line approach to anything having to do with isis." but the fact is, that will end up blocking a lot of speech. >> woodruff: all that and more, on tonight's pbs newshour. >> major funding for the pbs newshour has been provided by: >> ♪ love me tender ♪ love me true we can like many, but we can love only a precious few. because it is for those precious few that you have to be willingi to do so very much. but you don't have to do itu alone. lincoln financial helps you provide for and protect your financial future, because this, is what you do for people you love.

lincoln financial-- you're in charge. >> bnsf railway. >> xq institute. >> supporting social entrepreneurs and their solutions to the world's most pressing problems-- skollfoundation.org. >> supported by the john d. and catherine t. macarthur foundation. committed to building a moreit just, verdant and peaceful world. more information at macfound.org >> and with the ongoing support of these institutions >> this program was made possible by the corporation fore public broadcasting.g. and by contributions to your pbs station from viewers like you.o

thank you. >> woodruff: an emerging question in the presidential campaign: who would be the better commander-in-chief? donald trump and hillary clinton will both make their cases tonight on a television special. trump was out this morning, witp an early peek at his argument. >> today, i'm here to talk too you about three crucial words that should be at center, always, of our foreign policy: peace. through. strength. >> woodruff: donald trump's visit to philadelphia today was all about military policy. he called for big increases in defense spending to beef up the army, navy and air force-- after years of congressionally- mandated spending limits. >> as soon as i take office, i will ask congress to fully eliminate the defense sequester. i will submit a new budget to rebuild our military. it is so depleted.

>> woodruff: tonight, trump andm hillary clinton appear separately in a televised forum on national security. meanwhile, clinton's campaign unveiled a list of 95 retired generals and admirals backing her. that a came a day after trump's team touted a list of 88 endorsing him. meanwhile, former president clinton stumped in orlando,cl florida, and called out trump's attacks on his wife, and the family foundation: >> i mean, i saw where her opponent attacked my foundationp i think that is because he knew they were about to report that he used his foundation to givegi money to your attorney general, which is not legal. ( audience reacts ) >> woodruff: trump has denied d that his donation of $25,000 dollars to support florida'sdo republican attorney general pama bondi-- in 2013-- was meant to influence her office's possiblei review of trump university.

meanwhile, there is fallout from trump's meeting in mexico last week with president pena nieto. it has drawn wide criticism in mexico, and today, the treasury minister resigned, amid reports he arranged the trump visit. >> woodruff: we will turn to the changing shape of the presidential race-- as reflected in the polls-- after the newsen summary. in the day's other news: president obama urged americans to learn more about the world, and to reject isolationism. he was in laos, where he touredh a centuries-old buddhist temple, and then held a town hall with youth leaders from across southeast asia. >> i believe that the united states is and can be a great force for good in the world. but, if you're in the united states, sometimes you can feel lazy, and think, "we're so big, we don't have to really knowto anything about other people." and that's part of what i'm p trying to change.

>> woodruff: later, at a regional summit, the president met informally with philippinesl leader rodrigo duterte. the white house called off a formal meeting when duterte referred to mr. obama with foul language. the philippines also used the summit to highlight china'st expansionism in the south china sea. filipino officials released images said to show an increased number of chinese ships near a contested island. the summit issued a vaguely- worded statement, but did not mention china by name. the united nations reports intense new fighting in western syria has put at least 100,000 people to flight. they're fleeing homes in hama province, where islamist rebels launched an offensive last week, triggering government air strikes. an estimated 11 million syrians have fled since the war began in 2011. many of those migrants have gone to europe, and germany alone took in one million people last

year. that has caused a political backlash.ba but today, german chancellor g angela merkel went before parliament and insisted the country can handle the influx. >> the situation today is many times better than a year ago,s for everyone, but there remains a lot to do. change is not a bad thing. and we especially-- and i can speak for myself-- who experienced german unification have seen how change can be a very positive thing. that will not change. germany will remain germany, with everything that we love and treasure. >> woodruff: also today, britaia said it is building a wall at the french port of calais to stop illegal entries of migrantt through the channel tunnel. back in this country: the president has nominated a man who could become the first muslim american federal judge. abid riaz qureshi is a washington d.c. lawyer. he would need senate confirmation, but it is unclear if he can get it before congresb goes home next month.

on wall street, the dow jones industrial average lost nearly a 12 points to close at 18,526. the nasdaq rose eight points, and the s&p 500 slipped aan fraction. and, a woman who flew non-combat missions in world war ii, and died last year, was finally laid to rest today in arlington national cemetery. elaine harmon served with the "wasps"-- "women air-force service pilots." but last year, the army secretary ruled them ineligible for arlington, citing limited space. it took an act of congress to revoke that ruling. still to come on the newshour: the newest polls showing donaldt trump and hillary clinton in a dead heat; the two candidates' views on climate change; chicago's struggle to stem its growing gun violence, and much more.

>> woodruff: and now, we turn to politics, and a tightening race, both across the nation and in key battleground states. new polls indicate hillaryil clinton has a slight advantage, but donald trump is closing the gap in a few decisive states. lisa desjardins has our report.d >> reporter: there's a theme ina this week's political headlines-- different polls with one conclusion: nationally, the race between donald trump andd hillary clinton is getting closer. the big picture? clinton leads by three points, according to the "real clear politics" polling average. that is half of her lead a month ago. in other words, her post- convention bounce is over. she still has some key advantages, leading in states with a bonanza of electoral votes, like california and new york. she also has narrow leads in pivotal battleground states like colorado and virginia. also in clinton's favor: some demographics.

she is now far in front with at much-watched group: white, college-educated women, according to the "washington post." that's a reverse from 2012, when republican mitt romney won that group. but trump has strengths, too.t he is leading in the midwest overall, and in striking distance in michigan and wisconsin, which typically vote democratic at the presidential level. trump has also widened his lead among older, white voters. and, among those without college degrees, he now leads clinton in at least 43 states. what might be most important here is the timing. these dynamics are in play 60 days out from the election. in the past four elections, this is exactly when breakaway shift began in the polls. for the pbs newshour, i'm lisa desjardins. >> woodruff: so what do all these polls tell us about what's driving voters? and nine weeks out from election day, what do the candidates need to do to drive their message

home? we take a deeper look with dan balz, chief correspondent for the "washington post;" and carroll doherty, director for political research for the pew research center. and we welcome both of you back to the program. b dan, i'm going to start with you and your newspaper's 50-state0 poll out today. what do these numbers tell you about where the the race stands today? >> judy, they tell us severalse important things. first, that the race has tightened from where it was after the conventions.on hillary clinton got a bigger bounce out of the democratic convention than donald trump got from the republican convention,i and that moved the polls early in mid-august.in but what we've seen since then is a tightening. we've seen a different donald trump on the campaign trail. i-- i can't say what reason it is that it's tightened, but it has tightened. so that's the first point. the second point is that our 50-state poll underscores the degree to which hillary clinton still has an easier path to 270

electoral votes than donald trump does.p our numbers show that all she would need to do at this point is to add florida, and she would have 270 or more electoral votes. donald trump has a long, longna way to go to get there. he has very few options. he has to thread the needle, and she has many choices and many options, both in an effort to block him in the states he has to win but also to open up the map in some area where's she's might be able to expand. >> woodruff: and carrollro doherty, looking at the polls which you look at, which are a lot of them, including your own pew poll. what do you see there in terms of hillary clinton's path?nt >> well, i mean, we look at the national picture, and what you see is two candidates who just are viewed in extraordinarily negative ways, in different ways, but in negative ways. in our poll is in august, only three in 10 voters said hillary clinton would make a good or great president, and 27% said s donald trump would make a goodd

or great president. there are more people voting against than for these candidates in some ways. so negativity is really driving-- a motivating factor in this election. dan, given: so, that-- and we have been hearing about this negativity for some time-- given that, how do you explain hillary clinton'shi advantage? >> well, i think at this pointli she has become less unacceptabla than donald trump is. you know, we have-- as carroll said, we have to keep this in negative terms. one of the things we looked at we asked a question of, "do you think donald trump or hillary clinton, if they became president, would threaten the well-being of the united states?" 95% of the people across thehe country when you aggregate it up believe that one or both would be a threat to the well-being.e so there is great concern. these two candidates. but because of many of the things that donald trump hasas said up to now, the record he has established as a candidate has raised more questions about him than hillary clinton.hi >> woodruff: and, carroll

doherty, it is the case that questions are out there aboutbo donald trump, but there are also some opportunities for him,fo which show up in the polls. p >> absolutely.>> i mean, you know, 43% way he would make not just a bad but a terrible president.te there's probably an opportunity to move some of these numbers a little more in his direction. and some of these key groups, such as whites-- whites college degrees, importantly-- who have been trending republican in recent years, i think there is an opportunity there possibly to bring some of those voters backs >> woodruff: dan, we have already seen some movement on his part. as you mentioned, just since the conventions. >> well, we have. in the polling which we did, we we did, online polling with the firm survey monkey, he does have strength in the midwest. there are a number of midwestern state, some of which have gone democratic for five or six f elections in a row where he's doing reasonably well and is within striking distance.

so there's opportunity in those areas where the the electorate is older and whiter, and as carroll said, one of the problems he has at this point not-- not certainly that will be the the case onth election day, but right now, is with white college-educated voters and particularly white women,an who have college agrees.r mitt romney won whites with college educations with 56% of the vote, and hillary clinton is winning that group at this point. so donald trump needs to do that. and the other thing he needs to do, which you would expect over time, he will have some success on, and that is consolidating the republican vote in the way that hillary clinton has already consolidated the democratic vote. >> woodruff: why has he had a hard time with the white, more educated voter and republicans? >> well, and republicans, people forget that he won over a divided field, and didn't win a majority of all republican vote inic the primary.

so some of this is normal consolidation, and then some ofo it is self-inflicted in terms ot some of the things he said and done since then.ce >> woodruff: just quickly, q carroll doherty, how undecide read-- how many voters out there are undecided?e how malleable is voters' thinking at this point? >> the broadest range we havee been able to estimate maybe one in five.n it's down from where it's been.b you have to factor in the thirdr and fourth-party factor thisct time where they might go with gary johnson and jill stein but one in five, and that's less than prior electioning at this stage. >> woodruff: how many voters are there out there who still might make up their mind, might change their minds, go in another direction? >> it's very hard to estimate,i and i think polling doesn't hels us a lot on this. i mean, as carroll said, there'e a sizable number who say they haven't quite made up their mind or might change their mind. but as we've said, this is such an unhappy electorate, you haveu to think that most people kind of know where they're going too

end up, put they're not-- they're just so conflicted aboud the choice that they're not really ready to say with any certainty that they will definitely do that. so i think it leaves some uncertainty out there in where these polls might move over the next 60 days. >> woodruff: and quick final question to carroll doherty about these third-party candidates, gary johnson, and jill stein. you can say at this point howin much of a factor they can make? >> history suggests that measures of third-party support would decline over time, perhaps, but this is a very v unusual election. we had gary johnson at 10% in our most recent national poll. his profile voters, very young, very young profile voters for gary johnson at this point ?rd as you say, and, dan, i'll come back to you very quickly on this, typically the third-party candidates lose ground in thegr final weeks of an election. >> that's usually true, but i think the issue is if gary johnson were able to qualify and

hit that 15-% threshold, that would change that because he would then have nationalav visibility that he doesn't have at this point. p but so far, hesion not quite at that level. >> woodruff: well it's an election like we've never seen in so many ways. w thank you, both, dan balz, d carroll doherty. >> thank you, thank you. >> woodruff: and next, we turn now to our periodic look at the major issues facing the country, and where the presidential candidates stand on them. tonight, the cfocus is climate change. it is a subject that has gotten very little attention thus far during the campaign, even as it highlights one of the starkest differences between the candidates.atn,st william brangham has our report. >> reporter: this past weekend, the u.s. and china officially ratified the so-called parishe climate accords-- they are theco most substantial move by the world's nations to put some limits on the greenhouse gas emissions that are driving global temperatures upwards. and upwards they keep going. 2016 is on pace to be the hottest year in recordedye history, breaking the record set by 2015, and 2014 before that.

as many climate models predicted, a warming planet has coincided with increased heat waves and droughts, as well as more intense storms. glaciers and ice sheets continue to shrink, sending sea levels upwards and threatening coastal communities all over the world w with potentially catastrophic, costly flooding. michael oppenheimer is a climate scientist at princeton university. >> if we don't start with rapid emissions reductions and substantial emissionss reductions, we will pass a danger point, beyond which the consequences for many people anf countries on earth will simply become unacceptable and eventually disastrous. >> reporter: but the parisr: accords only set voluntary capsa on carbon emissions. so how seriously the united states follows through on these commitments-- as well as its other efforts to curtail carbon-- will fall largely on-- the next president. and while there are plenty of policies where clinton and trump have different views, there's probably no greater divergence between them than on the issuete of climate change.

one thinks it is real and poses a grave threat; the other thinks it's a fantasy.an >> i think it's a big scam, to make people a lot of money. >> reporter: donald trump has repeatedly called climate change a hoax.al he claims the planet is freezing, and that scientists are "stuck in ice." he has also argued global warming is a concept cooked uprm trump argues that environmentalu regulation is an enormous anti- competitive tax on u.s industry, which also threatens american jobs, especially in the coal industry. he says a trump administration will undo as many regulations as possible, starting with president obama's clean power plan, which has put limits onwe coal emissions. trump has also promised to rip up or cancel the paris accords, and block any funding for international climate change efforts. he supports the expansion of coal and oil and natural gas as main energy sources for the u.s. on the issue of renewables,s. trump has been largely silent.il >> climate change is such a consequential crisis to everyone in the world. >> reporter: hillary clinton, on the other hand, has repeatedlyep called climate change an urgent

threat, and one that is driven in large part by human activity-- namely, the burning of fossil fuels. clinton supports cutting carbon emissions, supports the goals of the paris accords, as well asri president obama's clean energy plan. clinton acknowledges these plano will cost coal industry jobs, and she has proposed a multibillion dollar renewable energy plan that she says will attempt to replace some of those lost jobs. to help understand what ato clinton or trump administration might mean with regards to climate change, i'm joined now by coral davenport, who is an environmental reporter for the "new york times;" and chris" mooney, who covers science andnd the environment for the "washington post." thank you both very much for being here. chris, i'd like to starty with you. before we get to the candidatesc let's talk for a moment about what is the current science tell us about the current impacts of climate change? >> well, 2016 is a very, very hot year.ye we're probably going to have three hottest year records in a row, 2014, 2015, 2016 topping

them all.em we've seen some really striking chiement-related effects on the world. most starkly this year i think the bleaching of coral reefs. r this is something climate scientists have been predicting for a long time and now it's happening. there are all kinds of impactski all around the world. we are losing more and more ice from the polar regions and, of course, temperature records are being broken. b >> brangham: anything you would add to that, coral? >> i would say the specific marker that a lot of scientists and scientific institutions have put forth is the warming of the atmosphere beyond 3.7 degrees fahrenheit on average. that's kind of the point at which a lot of scientists say we will be irrevocably locked in to a future of these climate impacts, and we're at the point right now where scientists say a lot of that is already baked in. there was a point-- >> brangham: there's no way we're going to stop hitting that mark. >> correct. the climatepoint in debate where how do we keep from

getting there? at this point, in terms of the emissions that are already in the atmosphere and the rate of emissions now being produced today, scientists are saying we're probably set to go past that tipping point, and the debate is really about how do you keep it are getting far, far worse? how do you keep the planet inhabitable by humans? >> brangham: okay, stayingha with you, i'm going to put the crystal ball in your hands now. it's january 2017, donald trump is inaugurated president. whate does u.s. climate policypo look like? >>ok well, most significant climate policy that donald trump has talkeddo about is he calls t cancelling the paris agreement. the paris agreement was a look accord reached last year in paris which for the first time joined almost every country on earth, over 195 countries, spoop committing to taking actions to reducing their carbon emissions. it was key for the u.s. to be a

centerpiece of that. the u.s. and china are the world's two largest emitters of carbon emissions, the u.s. historically the largest.a if the u.s. actually were towe pull out of the paris agreement, the deal could potentially unravel. and so the question now is what would happen in a trumpum administration, and the rest of the world led by u.n. secretaryn general ban ki-moon is trying to kind of figure out, how do we keep the paris accord intact ift there were to be a president trump? >> brangham: chris, take on that question, does the president have the ability, doli they have the leverses to rip up the paris accords?or >> it depends what happens during this administration before the next president comes in. there is a sort of rapid push reet now by the obamam administration and many nations of theat world to bring it into force, and once it actually enters into force, thenue have

to have 55 countries representing 55% of the global emissions in order to achieve that. once that happens there is language in the agreement saying you need three years beforeng yu can withdraw again, and then there's a year waiting period. so it sounds like from that language the hands of the next president could be tied if this thing enters into force, and we're going to have to see right now only about 40% of global emissions, 39% have signed on, and that's because u.s. and china did. you need india, canada, great britain-- you can do the math, but you have to get to 55, andnd you have to do it this year. then it would be more difficult to withdraw, but a president trump, if he didn't want to comply but couldn't make it go away, could just not cooperate. and it's not clear what would happen then. >> brangham: crystal ball is in your hands now.w january 2017, hillary clinton is inaugurated. what does energy policy lookoe like? >> i think it looks like a pretty strong continuation of obama climate policy. i think absolutely you could be

fulfilling the paris climate agreement and trying to reduce u.s. emissioning and the goal is to get them 26%, 28% below levels in 2025. i'm sure president clinton would be very much on board with that. i think domestically one of the most interesting things you would see under presidentre clinton would be the big energy infrastructure transition. how much solar do we install? i how do we integrate it on to the grid? how much of a role is natural gas going to play? >> brangham: corrable, i know you've been following this t somewhat. hillary clinton got into some trouble when he said as we make this push to renewables coal jobs are going to be lost. she put out a proposal saying we will beef up the renewables and try to save some of those jobs. how realistic is it? >> it's interesting to seeee hillary clinton-- even if it didn't come out quite the way

she meant it too on openly acknowledge that climate policy does take aim at coal.l coal is the largest source of planet-warming emission in addition the u.s.s so if you're trying on stop global warming you're going to take aim at coal.l. that means eventually coal community, the coal miners, coal-fired power plants, are going to get hurt. >> brangham: chris, lastm: question to you, the ability of a president on make meaningfuln contributions to this debate. if you were to go forward 50, 100, 150 years, would we be able to tell the difference between a clinton administration and a trump administration, meaningis how much influence do presidents really have on this policy when we're talking about a global problem? >> some significant influence,nc but i agree with you, that there are so many other things going on. for instance, one of the reasons the united states has actually been reducing its emissions in recent years isn actually that there's been a boom in natural gas. it's displacing coal. it emidst less carbon dioxide

when you burn it. i this is not really an obama policy. it's something that happened because of technology and the free market. and globally, you're seeing a big trend in installation of renewable energies across the world. you'll see huge installations of wind and solar in places like africa. these things are going to happen for largely nonpolicy free-markets. i think there are forces movingr not at the presidential level.en but at the same time, the obama administration kind of shows how you can use diplomacy to pring the most important countries together and get the whole world on board. so i wouldn't discount that, either. so i think that the world will continue trying to grapple with the climate problem, no matter who is u.s. president. but i think that depending who that president is, it can have a significant influence on the trajectory. >> brangham: all right, chris mooney, coral davenport, thankon you both very much.

>> woodruff: stay with us. coming up on the newshour: the woman who revitalized the traditional textile industry in laos; and what social media networks should do to combat terrorism online. but first, a bloody year in chicago; and residents, police and community leaders are asking why the violence is gettingth worse instead of better. it is already the deadliest year in more than two decades. 500 homicides so far; 90 in august alone. the killings were mostly clustered on the city's south and west sides. john yang went to find out why, despite changes and repeated calls for new action, violencevi there is so tough to rein in. >> reporter: on this busy street corner in englewood-- one of the hardest hit neighborhoods on the city's troubled south side-- it looks like a party. kids are playing.

the grill is fired up. in the past though, 75th and stewart felt like a war zone. >> this corner is a corner where a man was killed. well, several men. a woman was killed, and a child was killed-- a nine-year-oldar girl was killed washing her dog in broad daylight. and if men and women and a >> reporter: but for two summers, mothers against senseless killing, known aswn "mask," led by tamar manasseh, has been out on this corner and there hasn't been a single shooting. volunteer laura lambert comes from nearby hyde park. and 91-year-old edwina knight crosses the street every day from the house she's lived in for 57 years. >> show up, grab a lawn chair>> and pair of sunglasses and you can do this. you can change the world with that. >> reporter: but the moms of r "mask" are only on one corner, in a city of 2.7 million people. killings have spiked this summer. chicago has already recordedo

more homicides than it did in all of last year. >> that's what we're seeing t here, is the epidemic nature, the epidemic curve of-- ofde violence.of >> reporter: university ofy illinois at chicago physician gary slutkin says "epidemic" is exactly the right word. he argues that violence is a contagious disease. >> you're exposed to flu, you're more likely to get flu.u' you don't actually get flu without being exposed. same thing for t.b., cholera and violence. i mean, why does someone who wa exposed to child abuse, abuse, their own kids? that'd be the person who you'd think would be least likely to do it, because he knows how bad it was.ea but in fact, he's picked up this contagious set of behaviors. >> reporter: so dr. slutkin treats gun violence as a contagious disease. he founded "cure violence," now an international effort that trains former gang members and felons to stop violence in its tracks-- violence interrupters. >> they are always in the

community, aware of what's going on, and asking families and people, you know, "who's upset?" you know, who is-- somebody slept with someone's girlfriend, someone was disrespected, someone owes somebody money. and we can reach those peoplee with these health workers. they know how to cool people down, know how to buy time, >> reporter: chicago violence interrupter chico tillmon knows how to cool people down. he drove us around the south side last week, where much of the violence happens. >> wead a situation, maybe in early january, where twowh h individuals or two cliques were arguing, so one clique went into another cliques' neighborhood and got on facebook live and was like, "eff you all, we're in'r y'alls gas station." within 30 minutes on that walkth from the gas station back to thi house, two were dead, one was wounded.

>> reporter: it's not like this is a gang war over turf, this is just, sort of--t'hi >> interpersonal. i said something you didn't agree with, you responded negatively, it ended up in gunde violence. >> reporter: violence interrupter ulysses "u.s." floy was a leader in one of chicago' most notorious gangs, "the gangster disciples." >> i know i helped start this mess, so i wanted to help cleani it up. >> reporter: he told us gangs are very different now than in his day. >> one or two men control everything. now you've got a lot of cliques, different little, you know, gangs, split all over. they, they, they offsprings of the major gangs, what they call "cliques." oal and they just do what they wannw do, ain't nobody really in control, no structure, no rules >> reporter: the number of neighborhoods where chicago's branch of cure violence operates varies based on funding. but a justice department study found at one point, the group helped reduce violence by 40% to 70% in some of the areas where they were operating. today, they are in only five of the city's 77 neighborhoods.

you see these young men andse women in what looks like school uniforms. >> reporter: what are you thinking about when you see kids that age? >> man, i'm praying that they survive through this epidemic that's going on in the city. it's not a woodlawn problem, it's not a southshore problem,m, it's everybody's problem. and we don't understand that until the disease hits home. until one of our loved ones ists killed by gun violence. then we want to get involved. >> reporter: police have siezed nearly 6,000 illegal guns off the streets-- about one per>>s hour. but the summer surge comes as police face unprecedented challenges. the justice department is investigating their use of deadly force, and longstandingry mistrust in the police reached a breaking point last year with the release of a dash-cam video

showing a white officer fatally shooting black teenager laquany mcdonald in 2014.do chicago mayor rahm emanuel is under pressure to rebuild that trust. i >> i really see this problem as a, as a cultural problem. >> reporter: lance williams isth an associate professor of urbanl affairs at northeastern illinois university and an inner city youth advocate. >> this is not a law enforcement problem. i mean, you can hire all of the police that you want. you're not going to solve this problem because-- these young men are acting in, in alignment with their cultural value system. they need a cultural retooling process.em >> reporter: williams says it's a culture that's developed in the absence of working institutions and in the midst of crushing poverty. one big cause of much frustration: nearly half of black men in chicago aged 20 to

24 are not in school and are out of work, far higher than the national rate of 32%. >> there's a lot of rage, there's a lot of, of, of anger. they just see their lives, you know, just passing them by. they don't, they haven't been to school; they can't, they're,to they're not, you know, qualified for jobs. there are no businesses, viable businesses in their neighborhood, so they're really depressed, and then they're r self-medicated, through drinking and drugging. and the only individuals arounda them are other young african american males like themselves, who have these, these same forms of depression. >> reporter: another structuralu factor playing into the violence: chicago is one of thes nation's most segregated cities. >> all of the poor blacks live way, way, way, way away from affluent people, from the, the, the business district, from the tourist district. you know, you have some kids in these neighborhoods far south, that have never been downtown! and you have folks, in the white communities that have never been to the south side. so, what happens is, you have an

"out of sight, out of mind"-kint of deal. >> i was 23 when i went to prison. >> reporter: for chico tillmon, the violence is never out of sight or mind. turning other people's lives around came after he turned his own around. >> and being able to see all thd violence and chaos in the community that i once was a part of, and that i once helped produce, pushed me or gave me an obligation to make a change in that, in that situation of chaoc that was going on in theos community. >> reporter: since you got out of prison-- >> yeah. >> reporter: --you got yourou bachelor's degree. >> yes, sir. >> reporter: you got your master's degree. >> yes, sir. >> reporter: you're working onr: your phd. >> yes, sir. >> reporter: how long, how many years are we talking about here? >> five years. >> reporter: pretty determined. >> yeah.te f >> reporter: pretty motivated. >> yes, sir. i, i got out with a purpose, and i got out trying to not only do something that was beyond what i believed i could do, but toou inspire hope within all the people that i left behind in

prison. >> reporter: and back on thend corner of 75th and stewart, tamar manasseh is also determined that change will happen. >> it's going to take a lot of people all doing something-- not saying something, but doing something-- to fix that problem. and the doing something is theso sitting here, having ahe conversation. i live on this block with you, i live in this city with you, inyo this country with you and we're all affected by the same things. and sometimes when we don't talk to each other, we miss that. >> reporter: for the pbs newshour, i'm john yang in chicago. >> woodruff: and online, you can take a closer look at chicago'sy history of violence. we go back 50 years to count ala of the city's homicide victims. that's at www.pbs.org/newshour.

>> woodruff: now, how the u.s.f: government is trying to stem the tide of terrorism messages online, and the role of social media. the story is part of our coverage of the 15th anniversary of the 9/11 attacks. it was produced as part of tonight's "nova" special, "15 years of terror," reported by miles o'brien, and it's our weekly segment about the leading edge of technology. >> reporter: they called it "think again, turn away." the concept: use sarcasm as way to turn islamic state images into an argument against their grim techniques of terror. the creator and producer: the u.s. state department. today, everyone agrees the message was worse than ineffective; it played right

into the hands of the terrorists. >> you know, part if it is that i don't think the government should do snark or sarcasm. i don't think we're good at it. >> reporter: richard stengel is the under secretary of state fof public diplomacy and public affairs. he realized he was the one who needed to "think again." >> one of the things that weth realized is that we're not the best messenger for the message that we want to get out there. in fact, when we were a messenger at all, they use that against us. >> reporter: so they stopped trying to do it themselves, and hired some marketing pros. >> so, i think that they just was out of their league. >> reporter: tony sgro is anr: advertising and marketing veteran who is spearheading a novel competition for college students to create a counter-- or alternative-- narrative to the islamic state propaganda campaign. >> the government is not the most capable person to develop a counter-narrative for a 21-year- old. there's no credibility factor there. >> reporter: they call the competition "peer to peer."

undergraduates at two dozen schools all over the world have participated. in afghanistan, they created a campaign that included a talk show that focused on understanding the real message of the koran against extremism. they reached more than five million people. lahore university produced a plea from students to students to turn apathy into empathy. the winner of the competitionmp was the rochester institute ofe technology. students there came up with thie multi-platform campaign: >> it's beyond bombs, bullets, i and drones. it really is. we need that stuff.tu but we really-- how are you going to win the hearts andw minds? that's communications. it's a marketing communications issue. >> reporter: countering the messages is one thing. trying to stop them from spreading in the first place is

another. for years, the social networking platforms took a laissez-faireai approach to this problem. and it only got worse. but in 2013, things started to change. during a horrifying assault on a shopping mall in nairobi, kenya, attackers with the al-qaeda affiliate al-shabaab live- tweeted for hours, as they shot more than 175 people,an killing 67. >> that was the first time where twitter was actively removing the content that they were posting. >> reporter: jeff weyers is a police officer and terrorism analyst based in ontario canada. >> they were actively tweeting their attack online, and it was the first time we really sawnl that. isis completely blew that out of the water. they took that concept and magnified it by a million. >> reporter: today, twitter claims it aggressively goes after accounts linked to terrorists. the company says it closed 360,000 of them in the past year.

>> they were very much pushed into it as opposed to wanting to go down that road. and now, i have no doubt that they're spending millions of dollars just countering that message. >> reporter: facebook is the largest social networkingrg platform on the planet. it says it has a zero tolerance policy for extremists, but it must contend with a tsunami of content. facebook has more than one billion users actively posting every day. the company says about one half of 1% of flagged items are linked to terrorism. but that is still a lot of material. monika bickert is facebook's head of global policy management. >> we use photo matching technology to identify when somebody is trying to upload to facebook an image that we've already removed for violatinge' our policies. of course the image may or may

not violate our policies when it's uploaded again because it could be somebody who is sharing the terrorist image as part ofng the news story or to condemn violence.ol so we use automation to flag content that we will then have our teams review.r >> reporter: but are there more advanced ways to stop the extremist messages fromex spreading?sp is there a better technological solution? >> we have the technology to disrupt, not eliminate, but to disrupt the global transmission of extremism-related content.. >> reporter: hany farid is a computer scientist at dartmouth college. he has developed a technique to permanently attach unique digital signatures to images-- making it possible for the social networking companies to identify and stop the spread of videos made by, of and for f terror. >> so here is the actual raw frame that you're seeing. processing one frame at a time. and within a frame, we actually. analyze multiple blocks within it. the yellow crosshairs that you're seeing are enumerating the various blocks of the video that we're analyzing.

this yellow histogram is a distribution of the measurement that we're making from each individual block, and then that gets translated into an actual digital signature which i visualize here with a stemplot. >> reporter: the sheer volume of the problem is daunting-- billions of uploads a day, each of them with millions of pixels. can a computer possibly bebl trained to sort through it all and find the images that inspire new recruits, insight new violence and terrify us all? farid has already proven the technology works. he got the idea 10 years ago. the internet had become ae platform for child pornographers. applying digital signatures to those images has greatly reduced child pornography on the big social networking sites. >> so if there's just one image in an upload of yours that has child pornography, the account can be frozen. the contents of that account can

be assessed and new content can be discovered.be >> reporter: but extremist content is much harder to clearly define. the director of free expression project at the center for democracy and technology is emma llanso. >> the challenge with having a hard and fast rule against any a kind of content is that it really does shut down the opportunity for discussionsc around that sort of material. >> reporter: in june 2016, david thomson, a french journalist who reports on islamic extremism, found his facebook page suspended for three days. the offense? a photo he had posted in 2013 as part of the story he was doing included a partial depiction ofi the islamic state flag. a cautionary tale of the unintended consequences of targeting terrorism online. >> it seems appealing to say,et "oh, just have the major social media companies take a hard line approach to anything having to do with isis."it but the fact is that will end up blocking a lot of speech thatbl

will end up deactivating the accounts of many users.ny i mean, some of the platformss have had issues with just deactivating the accounts that women whose first name is isis. this is a difficult kind of censorship to enact.ns >> reporter: it's no longer just a war of bullets, drones and bombs. technology has created a new battlefield online, and civil society is still grasping for strategies to engage in a virtual battle. i'm miles o'brien, the pbs newshour, washington. >> woodruff: you can watch miles's full report, "15 years15 of terror," tonight on "nova," on most pbs stations. >> woodruff: now we return to laos-- a country of rich and deep history, scarred by american bombing during the vietnam war.

special correspondent mike cerre reports now from the capital, vientiane, on how one american woman helped heal frayed ties between the u.s. and laos by preserving tradition there... one thread at a time. >> reporter: the first americane president to address the lao people, from a podium decorated with traditional lao textiles,ti made by the first american company allowed to do business here since the end of the war. >> they actually arrived inac laos, found us and found something that we had that was appropriate. red, white and blue, of course.u >> reporter: how this american weaver from connecticut and her ethiopian-american husband helped save an endangerednd traditional craft, in a country ravaged by a "secret war" the u.s. waged here during the vietnam war, is the stuff of southeast asia lore. like jim thompson, the legendary, former c.i.a. agent who launched the thai silk industry after world war ii,

before he mysteriously disappeared-- carol cassidy helped resurrect the traditionae lao textile trade after their war. >> he had a great idea, which was to build a business based on traditional skills. that's something that we've done here in laos with lao textiles. we have done as well. i think one of the importanthe distinctions is i am a weaver.ea i have devoted my entire life since the age of 17 to weaving 1 and designing. >> reporter: when she and heran husband came here nearly 30 years ago as u.n. developmentye advisors, full diplomatic relations between the u.s. and laos had yet to be restored. americans were still viewed somewhat suspiciously by the communist lao government-- the u.s. having been on the losing side of the laos civil war and communist takeover. >> so it was really this rebuilding of lao americano relations that we have felt that. and my husband and i who, weba built the business together.

he is much more diplomatic thanm i am. and i think it's been very helpful, navigating the complexities. >> reporter: they eventually set up a textile business of their own with a core staff of weavers from the north, many of them the wives and mothers of the pathet lao communist forces who had been living and working out of caves during the nearly ten years of u.s. bombing. >> so the technology is very simple, its portable. when they fled the bombing they were able to take with them simple technology and their family traditions with them. >> reporter: the work is incredibly painstaking, from the hand dying of the silk, to spinning the silk yarn, and reproducing traditional designs from memory, using traditional lao looms many consider to be the inspiration for the first computers and binary code. >> the important part is this vertical heddle, and that is tht storage system which is the

floppy drive.ve this is the program, and down there and every string represents the program.he >> reporter: carol produces world-renowned textiles for top interior designer and architects around the globe. >> and this is part of the dying art, which is the creation of complex patterns. this is a skill that boua and i chan learned from their mother and grandmother. >> reporter: her real passionss and commitment has been using her weaving expertise to help empower local women, which she first started doing in africa. >> and most of the artisans are indigenous people, rural people. they are not the most visible and they don't have a voice, and that's really what i've been trying to do working with these communities. >> reporter: she might have started her globetrotting career as a weaver, but over the years since she's been here in laos, she has become an american ambassador and an evangelist fon the role of traditional arts in economic development, while

maintaining a country's culture. >> i feel that an important part of who you are is through yourth heritage, and it's through your past. in laos and in southeast asia, in general, textiles are among the most important parts of their past. so your uniqueness is expressed by what you wear, how you wear it, what you weave. the director of the i.m.f., christine lagarde, was heree earlier this year-- which was a very important visit because wey had the opportunity to show her that stability, ethnic identity, employment, women empowerment culture is all interwoven in what we're doing here at lao textiles. >> reporter: carol lives and l works out of a french colonial home in the center of vientiane, where she also raised twosh children. her husband and business partner dawit seyoum takes cares of the operational side of the business. it's run more like an extended family co-op, with many of the original weavers and their children still working withng them.

>> and because we've been able w to retain our staff for more than 25 years through our pension plan, through our healt plan, we've been able than to weave these extraordinaryes projects. >> reporter: she has experienced firsthand the many changes laos has undergone since coming here in 1989, when the only way to cross the mekong river inton thailand was by boat. vientiane, the capital, had noth traffic lights or buildings taller than a palm tree, and everyone in her neighborhood knew each other. >> and you go away for a month, and this was all old buildings that came down, and i guess thih is going to be a hotel. >> reporter: as successful as her business has become, both ab an enterprise and a model for maintaining traditional textiles, her biggest concernsxt are with the latest assaults on traditional weaving from theom modern reality of mass production of textilesod throughout the region. >> oh, no, this was not made in laos. we don't have the industrial capacity.

in laos, we still handcraft hign quality, excellent textiles. >> reporter: having embraced the lao culture as completely as she has over the years, she has faith that traditional weaving will somehow withstand yet another challenge to its legacy. >> where your spirit goes inoe life, in marriage, and death, are all interwoven in the story of the textiles. >> reporter: for the pbs newshour, i'm mike cerre in i vientianne, laos.os . >> woodruff: and that's the newshour for tonight. i'm judy woodruff. join us online, and again herehe tomorrow evening. for all of us at the pbs newshour, thank you and good night. >> major funding for the pbs

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