captioning sponsored by newshour productions, llc >> woodruff: good evening, i'm judy woodruff.sh on the nr tonight, students return to the florida high school leere a shooting 17 dead, as president trump meets with both democratic and m republicanbers of congress to talk about new gun heasures. also, white house communications director, hope hicks, mr. trump's lst serving aide, announces she ll resign.me then, securingca's ballot box-- wi midterm elections around the corner, fears grow of further russian meddling in the nation'semocracy. and, decoding north korea's nuclear abilities-- how researchers are dissecting the regime's propaganda for clues inside its secretive missile program. >> every time the north koreans conduct a missile launch, we try

to figure out where it happened. we take all the pictures that they relsed and we try to, what we call, geolocate them. >> woodruff: all that and more on tonight's pbs newshour. >> major funding for the pbs newshour has been provided by: >> the lemelson foundation. committed improving lives rough invention. in the u.s. and developing countries.le on the web at melson.org.

>> supported by the john d. andr catherine t. mur foundation. committed to building a more just, verdant and peaceful world. more information at macfound.org >> this program was made possible by the corporation for public broadcastinut and by contrns to your pbs station from viewers like you. thank you. >> woodruff: it's beetwo weeks eosince a gunman killed 17e at a high school in parkland, florida. today, the school reopened, as talk continued in washingt on what to do about guns. john yang has our report. >> yang: students returned to marjory stoneman douglas high school classrooms this morning, amid reminders of the valentine's day killings. >> we're never going to be back

to normal, but it's going to get us in the right direction againi >> yang: mak memorials were piled high with flowers. some brought signs of encouragement. there was a heavy police presence. >> oh, wow there are a lot of. police oh my goodness, yeah that is a lot. >> yang: the nearly 3,300 t students beganhe day with fourth period, the classes that were underway when the shooting y arted two weeks ago today. >> we start the the class where the event took place, so that's like gonna be a little d and like weird. but i'm just glad to see everybody that i spent the hard time with and see that they're all okay. >> yang: 14-year-old jamie guttenberg was killed in the shooting. today, her father tched as classmates went back to school without her. >> it's the safest school in america right now. so, as long as it stays that way, i guess i'm okay. and i think it'll stay that way for e rest of this year with all this significant presence

and efforts to strengthen and fortify it. itmy still the scene of wher daughter, unfortunately, was murdered. >> yang: a teacher posted a picture of a therapy dog in her classroom. many students say they would keep fighting for stricter gun control laws. >> we're still around, we're still kickg it, we're still trying to send a message. don't forget about us,se we can't forget about those who we lost. >> yang: t a major gun retailer, dick's sporting goods, announced it'sno waiting for new legislation. c.e.o. edward stack said they companwill stop selling assault-style rifles and will not sell any gun to anyone under 21.re >> we weo disturbed and saddened by what happened we felt that we really needed tdo something. we did everything that the law required and still he was able to buy a gun. >> yang: the 19-year-old shooting suspect, nikolas cruz, legally rchased a gun from dick's last fall, but not the

a.r.-15 he allegedly used in the shooting. at the white house, president trump met with a bipartisan group of lawmakers to talk about gun control legislatio >> as we continue to mourn the loss of so many precious you lives, we're determined to turn our ief into action. >> yang: mr. trump backed better background checks for gun purchases, including private sales, like those at gun shows, and arming teachers and other school workers. >> i really believe it will prevent from ever happening. they are cowards, they're not going in knowing they'onna come out dead. >> yang: in some of the worstot school sgs, though, like columbine, virginia tech and sandy hook, the shooters killed themselves.an the president underscored his differences with the powerful national rifle association on raising the age for buying assault-stypons and saying that guns should have been preemptively taken away from cruz whether "they had a right to or not."il

he also said ato pass conceal and carry laws across state lines should not be part of a bipartisan igll. >> i'm aan of the n.r.a., these are great patriots, they love our country, but thatav doesn't mean ito agree with them >> yang: democratic senator chris murphy of connecticut told mr. trump that passing legislation required presidential leadershi >> mr. president, it's going to have to be you who brings theic repus to the table on this because right now the gun lobby would stop it in its tracks. >> yang: as the president and lawmakers seek common ground in hopes of tryinto stop the loss of life that the students in for the pbs newshour, i'm john yang. >> woodruff: in a related development, police in dalton, georgia arrested a high school teacher after he barricaded himself in an empty classroom, and fired a handgun once. no one was hit, but one student sprained an ankle running. w there's d on the teacher's motive. white house communications director hope hicks announced today she will be leaving the trump administration in the coming weeks.

the 29-year-old is the fourth communications director in president trump's 13-months in office and one of the president's longest-serving advisers. hicks' announcement comes a day ied before the house intelligence committee as part of its ongoingve igation into russian interference in the 2016 presidenhlal election. parker is a white house reporter for the "washington fost." ashley, thank yojoining us. so, what is known about why hope hicks is doing this? >> so, i first should underscore that this is an incredibly stunning development. there was a sense that even in a chaotic andus tumulthite house, that there was one person who would be with president trump through the end of his term or potentially two terms, is would be hope hicks. our understanding is that she did actually make this decision before yesterday's tetimony on capitol hill. and she has told people that she

basically wants to spend-- be closer to homto her family in connecticut, that three yearscu d solely on one thing and working in this incredibly high-pressure an high-intensity environment just talks a toll on anyone and s reaized it was her time to move on. i do have to say, this comes as she, herself, was under a lot of personal stress. there was not just that testimony. she had been romantically linked to staff secrary rob porte who was forced out of the white house amid allegations of domestic abus and more broadly, right now, the mueller probe isntensifying, and it feels like it's creeping closer to the west wing and the oval office. hope hicks is someo who literally sits outside the oval office, and is intiedmately invon everything. if there is someone who would sort of know every little bit and piece of what is said and done in that white house, it is hope hicks. >> woodruff: she sits right

next to the president, has the closest office t h. and, ashlee, there was reporting yesterday after her testimony that she had told the committee members that she did sometimes tell what she called "white lies" for the president. there's been a lot of speculation about tt and whether that had some effect on this. >> that's righ , and again, she has told people-- she had told somele pebout this decision before her testimony, where she mentioned the whe lies, and she claims that that-- the russia investigation in general, has nothing to do with this. but you have to recognize that, agai more than anyone in thi white house, hope is in an incredibly precarious position because she was often called upon, by her ssown admin, to sort of fib for the president, and,e ou know, maybgage some some misdirection. and there's no crime, as we unfortunately all know, with lying to the media. but you cannot lie under oath to congressional investigators and you certainly cannot lie when you speak to a special counsel. >> woodruff: ad just quickly,

ashley, you pointed out she's been at the president's side for long time. we said longest serving aide. and this does follow a numb of other top advisers to the left just ino hav the first year. >> that's another incredibly important point. and this is a president who runs the white house ke a family business, and he likes to surround himself with familiar faces and people he's comfortable with. and with hope hicks leaving it leaves him increasingly isolated. all these familiar face, people he's known forever, are gone. >> woodruff: ashley parker with "the washington posmu" thanks ver. >> thank you. >> woodrf: in the day's other news, president trump got into a new dispute with his attorney general, jeff sessions, over the russiinvestigation. sessions had announced his inspector general will look into whether the f.b.i. abused its surveillance pows. this morning, mr. trump tweeted the review "wi take forever." and, he asked: "why not use justice department lawyers? disgraceful!" sessions answered in a statement

that said: "i will contie to discharge my duties with integrity and honor." meanwhile, former trump campaign chair paul manafort pleaded not guilty tay to updated federal charges in the russia investigatio they involve money laundering and acting as an unregistered foreign agent. the judge set his trial date for september 17th. in syria, there was no sign of a truce in the damascus suburbs, despite russia's call for a daily pause in fighting. no civilians turned up at a checkpoint to exit eastern ghouta today, as syrian and russian forces waited. no aid went in, either. meanwhile, in moscow, russianpr ident vladimir putin claimed some civilians did get out of eastern ghouta, despe rebel attacks. ( translated ): there is constant shelling from there. or some days there are up to 50 or 80 rocket andr strikes. we have managed to get out quite a big group of those who wanted to leave from there.

st the second group that prepared could not leave because the militants just did not give them an portunity to do that. >> woodruff: syrian war monitors said they coulnot confirm that anyone has been evacuated from eastern ghouta. the government of afghanistan offered today to recognize the cataliban as a lawful poli party, if it joins in a peace process. the goal is to end more than 16 years of war. president ashraf ghani addressed an international conference in kabul, and he called for the militant group to help "save the country." >> ( translated ): the taliban leadership and every other taliban, you havthe decision to make. accept peace, accept it with honor and come together, so we can make this country safe and secure, which is the heritage of our saes, jihad and our blood. >> woodruff: the taliban had no immediate response to the offer. back in this country, the u.s. supreme court will decide a case that focus on what to wear when voting. justices heard arguments today

on a minnesota law that bars most politically-themed clothint he polls. a number of states have similar laws, but minnesota's is broadem tht. s achers in at least two west virginia counte refusing to go back to work tomorrow, after a five-day strike.he that's despiteovernor's offer to raise pay five percent. most teachers are expected back tomorrow, but some are holding out for lower health insurance premiums. the u.s. olympic committee announced a shakeup today, amid the scanl over sexual abuse of young gymnasts. c.o. scott blackmun said he's resigning after being diagnosed th prostate cancer. the u.s.o.c. is investigating how blackmun and others handled the abuse ise. on wall street, worries about higher interest rates triggered another sellff. the dow jones industrial average lost 380 points to close at 25,029. the nasdaq fell 57 points, and

the s&p 500 dropped 30. both the dow and t s&p had their worst months in two years. and, president trump and congress paid tribute to billy graham today, as his casket arrid at the u.s. capitol rotunda. ust thee evangelist is fourth private citizen to lie in honor there. the president, lawmakers, and hundreds of others turned out.or senate my leader mitch mcconnell eulogized the man who came to pastor."s "america's >> the man we recognize todayed shhe gospel with more people face-to-face than anyone else in history. his clear voice thundereded through paents, stadiums, auditoriums, parks and plazas the world over. his warmth and graciousness lit up living rooms and touched hu.reds of millions of hear >> woodruff: billy graham died

last week at 99. he will lie in honor through tomorrow. his funeral will be friday in charlotte, north carolin still to come on the newshour: n states secure their voting systems in time for the midterm elections? spying on north korea, using publicly available data. plus, i sit down with south korea's top foreign policy adviser, and much more. >> woodruff: the department of homeland security is pushing back at reports that say voter registration systems in seven states were compromised byor russia bthe 2016 presidential election. >> the threat they posed has been confirmed by the heads of all s. intelligence agencies. yesterday, the leader of the national security agenre

testified behe senate that president trump has not granted any additional authorities to respond to this threat. we get reaction now from david becker, the founder of the eenter for election innovation and rearch, and denise merrill. she's the secretary of state inu connec she oversees the state's elections. welcome to both of you to the newshour. david becker, to you, first, in sum, what did the russians do to election systems in this country in 2016? >> well what, we know from testimony from the intelligence mmunity and elsewhere is that they attempted to probe or scan nveral state systems, probably moably, voter registration database systems. almost all o those scans and probes were unsuccessful. there was one instance in illinois wre they successfully accessed voter data, about 70,000 records or so,in jun and july of 2016, but no records were altereder delted. we also know from the intelligence community and from ltiple investigations a around the country, that there

were no successful efforts to ange votes or change vote totals or tallies throughout the united stas. >> woodruff: denise merrill, what about tbhapped your state of connecticut? we know there was an effort made by the russians there? >> yes, we were one of 21 states, apparently, that were scanned, at least, by russiani. addresses. again, our firewalls and our systems held. they were trying to get into our voter registration database, which i think is similar to what happened in the other states.th i thin good news they didn't get in. and i think that's pretty much true in all the other states with that one exception that david mentions. >> woodruff: and denise merrill, staying with you, what evidence or belief do you have right now that that i ever continuing to try to do that in this 2018 midterm election year? >> well, i do think the threatt of russian rference in our election is real. of that,me convinc not only by what has happened, but by what could happen.

i think we're all on alert now that there could be other attempts. stly think that the biggest goal that they have at this point is to sow distrust in the american public in elections. that may be the most dangerous thing of all. >> woodruff: david becker, why are u.s. election systems? vulnerab >> well, the more we rely upon technology, all technology has some vulnerabilities to it. and that's why it's fortunate have systems in place to double check theechnology. so, for instance, paper ballots, auditable ballots that can be audited after the election ismp very, veryrtant. the good news is 75% to 8% of americans currently vote on paper, and that number is s increasing as virginia ved to all paper. pennsylvania is about to move to all paper. and about 17 states are considering ways to improve their audili. system that are very, very important to make sure we can trust electronic machines thatn are cong our votes. but the good news smost states are doing it, and even more states are movng in that

direction. >> woodruff: and david becker, just to clarify, this is a state-by-state situation, right? there's no federal election overlay, as i understand it. >> that's right. d a major federal election, we not only don't hold one election or 50 elons. we actually hold about nearly 10,000 electionsl because of the local jurisdictions are actually running the elections. that does give usome protection against hacking because it's difficult to hack into 8,000 to 10,000 different systems. but we do have to be vigilant. secretary rrill is exactly right-- russia is trying to do this. the intelligence community is unanimous in that determination. and their goal is probably not actually to change vote totals but, rather, to get us all to lose confidence in our o election system. so it's very important that we all understand that the election officials, like secretary merand i will her colleagues, are working very hard with the-- with federal agencies and other agencies to security election systems, as they've never done before. >> woodruff: well, secretary

merrill, denise merrill, what is it that connecticut need what do you need in your state to be sure that there's not interference this year? and how much support, what of support are you getting for the federal government to make sure that that happens? >> we, of course, as a state, already have a lot of equipment in place-- cyber hygien the kinds of firewalls, i guess you'd call them, against this sort of thing. but we are getting help now from the department of homeland security. ey do have resources thacan help, not enough of them, and not enough to go around. so i think we could use more of that. some states are much further along than others, as well. and, of course,, you know, there are some federal laws that came into play after the 2000 election, which was the last time this sort of thing came up with the hanging chads, and sofo h. and the "help america vote" act did provide much of the funding that you're seeing in place for the current election systs. they're getting older. so at some point, we should look

at replacing some of tt. >> woodruff: and i think what we've seen in the news in the last few days is questions,bo concerns whether the federal government is taking this seriously enough, doing enough to help the states. and i just hear you say, denise merrill, that u're not getting all the help you need. >> no. and i'mot sure it's d.h.s.' fault. i think they are trng to be helpful, but they have limited resources. and i was rathuter surprised, b not entirely surprised, to learn of the statements by the b.i. director, i guess it was yesterday or today, that he did not have direct authority to act to prevent some of this. so i am concerned about that. i think the state officials, election officials all over the country are .on ale we're ready, willing, and able to help. we're very familiar with this risk assessment kind of thing. we've been doing it for years in elections. this is just a new ven a new kind of a threat. and i'm waiting for a direction from them. i think they could be immensely

dohelpful. we'rg better. we have a great communication system we're developing but they could do more for, us yes. >> woodruff: very quickly, in just a few saturday, david becker, what would be most important to hetates aroundlet country harden up their systems sore they're not vulnerable? >> well, there's unprecedented cooperation between the federal government and the stes and the local election officials but the one thing they really need dright now is resources funding. there's no finish line in cyber-security. r-security,prove cybe the bad guys get better, too. there need to be better fundin streams, perhaps at the state level and congress. >> woodruff: david beckh the federal center for election inoovation and research. and secretary of state ce # denise merrill from connecticut. we thank you both. >> thank you. >> thai.

>> woodruff: over the last two weeks, miles o'brien has takenn ustour of what's publicly known about north korea'sap nuclear s program. in the third and final part of his series, les looks at how ose bombs might be delivered. tonight, on the leadge of science, the sleuths searching through open source clues to nogh korea's fast-developin missilorprogram. >> rr: north korean missiles are flying much farther and muchore frequently since kim jong-un became supreme leader in 2011. he has reigned over more than 80 launches, so far. the outside world watches warily, with a network of early warning radar, ssors and satellites that track the missiles in re time to be sure they are indeed tests. once the basic data is released by norad, the sleuthing work begins for people like jeffrey lewis.

>> we can usually add quite a bit of detail because we can model the missile and we can ncually find the precise l location using photographs. >> reporter: lewis is director of the east asian nonproliferation program at the middlebury institute ofte ational studies ater montey. he and his team look long and hard at the images released by the regime. >> every time the north koreans conduct a missile launch, we try to figure out where it happened. we take all the pictures that they released and we try twh we call, geolocate them we're able to see where the llunch occurred, and we are even able to here kim jong un was standing when he watched it. >> reporter: lewar and his team dialed into a global network of armchair analysts on a similar mission. marco langbroek is a longtime amateur blogger based in the netherlands. >> the measurements is that you have a very nice calibration of what directions is where on the horizon. >> reporter: he gave me fascinating glimpse into a realm tha"ounds like an oxymoron;"

open-source spying." the north koreans released these images of their last andargest missile test of a hwasong 15 in november of 2017. langbroek spent a lot of time charting the stars in these images. >> so we can build a timeline of events in the moment this truck arrives, starts to erect its missile and up to launch. >> reporter: based on this, langbroek estimates it took two hours for the north koreans to launch the hwasong 15. langbroek knows the location of those buildings thanks to lewis and his team. d all began with a 13 sec video showing kim jong-un's father and predecessor, kim jong-il, in a building with some no dong missiles in th 2000s. >> it has these very unusual windows along the back and the side and in the roof. we thought, "if we know where the windows are then we cane model side of the building, use that to model the

outside of the building., and th we know approximately where to look, we can find this thing in a r:tellite photograph. >> reporhey made a 3-d ckdel of the building and the missile carrying tased on the images, and homed in on their quarry. >>nd so, there it is. you could see it's exactly the building that we imagined. and you can see the reason that they added t big skylight was precisely so that the vehicle would fit in and that they could lift the missile all the way up. >> reporter: similar techniques can alsoive outsiders an inkling on how successful a missile test is. >> what u want to do is somehow correct for this distortion. >> reporter: langbroek found this image of kim jong-un very telling. the map evidently shows the intended trajecty of the missile. >> you can compare whether whatt they mo do with their launch actually matches what the rocket really did.te >> repor he uses software that corrects the distortions caused by the perspective of the ra. he compares the red line on the map with trajectories of the

test released by western military sources. t doing all s tells you pretty much they had a successful test i guess, right? >> yeah, what it basically shows that if they do the best, they can actually aim their missiles quite well, which of course important in terms of when you are going to use them in a real war situation. >> reporter: so far, north koreans have tested their large camissiles on highly ellip suborbital flights. flatten out the arc and a hwasong 15, can reach any location in the continental u.s >> t a model of the hwasong-12. this is the missile that was being lifted by the crane. >> reporter: lewis also measures the prowess of north korean missiles by timing their acceletion off the launch pad. >> if you know how hhe thing is and how quickly it is being pushed, you know how much po being used to push it. so, we've been able to estimate the strength of the north korean engines d as it turns out, we get exactly the same number as the leaked u.s. intelligen community estimate. >> reporter: they sussed out its

weight by looking at these images of kim jong-un watching launch preps for a hwasong-12. the key: a logo of a japanese company on the crane. >> and so by modeling the building and the missile and the crane, we were able to figure out how far the arm was extended, the angle that the arm was at. and then, we could look at the specifications for this particular commercial crane and figure out approximately how much the missile weighed. when we did the crane analysis, one of the things we discovered is that north korea's missiles were more advanced than we thought. the missile itself was still strong but much lighter than we expected. no reporter: lewis believes the h koreans have the technology and knowledge to mill so called "isogrid" pieces like this. they are as strong as a solid piece of metal, but much lighter. is hard to do unless you have modern computer numerically controlled machine tools and that's precisely what kim jong- un washowing us in that building. it was that they have the capability to this sort of

thing. >> reporter: but they also have the capability to doctor images, lewis discovered kim jong-un's ears are often photoshopped. and remember that starfield marco langbroeanalyzed? a later image from the same vantage point, of thlaunch itself, shows stars that would be behind the camera. >> the star backgrounds are dramatically different. because here it shows orion and here it shows a part of anyomeda with andromeda gal over here, and these are completely different parts of the sky. this is in the south-southst and this actually in the northwest. so that's not possible. they should show the sky background but they don't. >> reporter: what would be the reasons to do that? >> i think it simply for aesthetics. they wanted a very nice propaganda pictures and ofor course, what'sbeautiful is propaganda than having your i.c.b.m. soaring to a star- spangled sky. it's aesthetics. >> reporter: but you have to wonder why they tip their hand as much as they do? >> if i we the north koreans one thing i might do is just stop all of this propaganda

altogether. but then, they lose the deterrent value, right? they lose the threat because if you can't see it, then you don't ow it's real. so, i think we're both locked in this game ere they want to ll us some things and not others, and our job is to figure llt what those other things they don't want to te us are.ep iborter: until technology made all this possle, this job fell in the realm the professional spies, shared only with policy makers that have a security clearances. >> this was actut ly my very fiip. >> reporter: nuclear physicist sig hecker is one of those people he ran the los alamos national laboratory from 1986 through 1997. he supports the open source sleuthing. >> the open-source infor the public and what's actually important, of course when you do open-source, you do get more eyes on the problem, more people to think about it, more people who think in ways that perhaps and north korea might think that then what we havin our

government. >> reporter: in ct, marco lanbroek says his website is routinely visited by c.i.a., and jeffrey lewis and his team gets invitations to brief government analysts. so what is the take-away for the concerned public? even though north korea has not proven it has a weapon small and robust enough to survive the fiery re-entry into the atmosphere, it can launch a missile with enough payload to carry a bomb to anamerican ty. for the pbs newshour, i'm milese w >> woodruff: you cch all three of miles o'brien's reports on north korea's nuclear capabilities online at pbs dot org slash newshour. stay with us, coming up, a mysterious and fatal disease affecting el salvador's sugar cane workers. plus, our racial divide: a new

look at race ithe u.s., 50 years after a seminal report. but first, staying with the topic of north korea, since the start of the year, tensions have lowered on the korean peninsulae in the pasweeks, north koreans participated in the olympics in south korea. kim jong-un's sister attended the games, and gave the president of south korea a letter from her brother, viting him to north kore and earlier this week, south korea's president moon jae-in said north korean officials told him that the north was willing to have a dialogue with the united states. so where do things stand nowh between nod south korea, and with the south's american ally? for that we turn to moon chung- in. f he is senieign policy and unification advisor to south korea's president. mr. moon, welcome to the newshour. the trump admini describes its policy toward north korea as "maximum

pressure." you said yesterday that it should be instead "maximum prudence." why? what did you mean? >> what i said is our presideng is tak maximum prudence in dealing with north korea and in dealinwith the united states. we are hoping that our president would turn maximum pressure into some kind of dialogue and negotiation through prudentpo cy. >> woodruff: what do you think the chances are that the u.s. and north korea will talk some time in the near future? >> right now, it is hard, but if north korea continues to show the behavior, test launching ballistic missile, maybe there's a good chance. north korea has got to show self-restraint behavior. ere were to: if t be u.s.-north korea talks, some

denuclearization be themain focus of those talks? >> sure. because denuclearization of north korea must be the goal of the united states and south korea.s >> woodruff: ik because, clearly, there are human rights issues, so many other issues, that could be discussed between the two countries. >> no, i think it is better to prioritie . right now st urgent issue is nuclear missile issues. it is better to focus on that agenda. if we come up with human rights and democracy to the forefront of the negotiation, north korea esll regard is as a hostile act by the united st therefore, it is better for us to focus on the nuclear and missile sues, the follow up with human rights and democracy, when and if there is some degree of confidence, trust blding between the u.s. and north korea. >> woodruff: should there be any preconditions before there

were talkrbetween north a and want united states? >> i personally believe that it is better to ve a talk without any precondition. because time is ond noboy's side. >> woodruff: and does the u.s. agree with you about that? >> i hope that they would come up that kind of conclusion. >> woodruff: how ofen is your government talking to the north korean governme? >> on the occasion of the pyeongchang olympics, south korea was able to resre all chables of communication with north korea. therefore, it would be muchsi for us to talk with north korea now and in thee. futu but up until the end of december last year,here was no channels of communication. there was a big change. >> woouff: there is, clearly, discussion about military exercises that the.s. and south korea are scheduled to carry out in the comiewng months. the north koreans say they, viously, don't like these

exercises. they feel threatened by them. could those exercises be delayed? does the u.s. and south koreaon agrehether to go ahead with them, the timing of them? the american embassy in seoul made it very clear yesterday there would be no more delay of the schele of our joint military exercise. but, however, as to thejoint military training, which is different from exercise, thecore d be some room for adjustment. but llcannot you what would be the futurerospect. >> woodruff: and is that-- is that going to be helpful toward getting the north koreans to sit down at the table? >> i don't know. north korea is likely to respond in very historic manner, the south korean effort to persuade to keep the-- despite the join military exercise. >> woodruff: how worried are people outh korea by a

strike by north korea, either a deliberate strike or a miste? >> we are very fearful of the north korean threat. north korea has now nuclear weapons capability. north korea has deployed more than8,000 long-range artillery pieces. they can in the seoultr olitan area. the dilemma is this: if we show panic, then we become the hostage of north korea in the tactical move. th's why we in south korea tend to be much more calm over the north korean threat. it is ironic to note that america is faray from north korea, but america is mt concerned, and japan still quite far away from north korea, but japan is second in terms of a threat perception. but south korea, even ough under the immediate north korea, said we show calm behavior. i don't know whether it's good or not.

but that is the way we should handle north korea. >> woodrf: what about a strike by want united states? # on north korea? how much does your country think and worry about that? >> yeah, we are very much worried about american unilateral military tion on north korea because north korea is most likely to retaliate against south korea. then there will be a full-blown conflict escalation. collateral damage would be catastrophe. therefore, south koa cann really tolerate american military action on north korea. that is why we have behing for the idea of diplomatic resolution of north korea nuclear problem. >> woodruff: well, mr. moon chung-in, we thank you very much for coming in to talk with us today. >> thank you

>> woodruff: in many central american communities, a mysterious disease has affected >> woodruff: apologies about the audio problem. in many central american communities a mysterious disease has affected farm workers. salvador, special correspondent fred de sam lazaro focuses on workers who are caught in the middle of trying to eke out a living while maintning their health. this report is part of fred's series "agents for change." r

eporter: the cutters begin early, trying to sneak a couple of hours before the tropical suc begins tch the sugar cane fields. it's di trty, brutal wot requires the stamina of thed young ysically fit, the exertion likened to running a half marathon every but 20 years ago, doctors began noticing an alarming increase in the number of these young workers across central cmerica who weing into hospitals with a mysterious, ultimately fatakidney ailment. dr. ramon garcia is a kidney specialistn el salvador's capital, san salvador. >> seven to eighdeaths every day in this small couny. it's 10 to 12 times more than the expected death rate. this is a silent massacre. >> reporter: as drgarcia and others began to investigate, they discovered that on some farms, nearly one-fifth of sugar cane workers were suffering from chronic kidney disease even

though they had none of the usual risk factors such as high blood pressure and diabetes. jose monjares has been a cane cutter most of his adult life in the small coastal region that is the disease's epenter. his father and uncle died from it. he got his diagnosis years ago. >> ( translated ): it camen very suddenly: back pain, fever, vomiting. >> reporter: the illness forced nom to stop the grueling working as a cutter so he works as a field assistant. he needs the job, he says, even though the wages barely cover the cost of medications to slow the disease. >> ( translated ): i have to take care of myself and watch my , et. because if i donll have to get dialysis and that just means death. >>oeporter: ramon aguilar, heads a cooperative of small farmers in the region, says at least 10 ohis members died last year from kidney disease.

>> ( translated ): there may ve been others who died who weren't diagnosed. here in don't want to recognize this disease and that an epidemic exists. >> reporter: dr.r arcia and otsearchers, including a team from boston university, have conducted several studies trying to determine the cause. initially pesticides were considered a likely culprit, but there was no explanation why these chemicals dn't have a similar impact in other places they are sprayed, including the united states. dr. garcia says one thing they believe may be contributing factor: t severe dehydration of the workers, which prevents the kidneys from functioning fully. >> it's too hot, simply too hot. you cannot drink enough water at the same pace that you are losing it in sweat. we're not sure if this is the only cause or a mix of causesut

thatogether are producing the disease. a >> reporteresearchers scramble to find the root cause of the disease, some groups are sing on improving workin conditions. some regions of the wove mechanized cane harvesting. it lowers the financial cost but hewould create a social on, says sebastian teunissen of the netherlands-based group solidaridad. >> something has to change. it could be mechanization. it could be that farmers work together in cooperates so they ke effective use of the land. but that means surplus labor. i one of theues really is where is that labor going to go in the coming decades? >> reporter: his group and others try to coax workers to take regular rest breaks and shelter from the intense sun and to hydrate whether or not they are thirsty. it managed to get one of the largest sugar producers in the country to make this company policy. problem is: just 8% of the sugar processed here comesm

company land. most comes from small farmers, 2,000 of them, says owner juan wright. >> just to convince people that the practice of resting and taking water with certain frequency is hard to get across. >> reporter: it's not hard to understand why. here in the field there's every ngcentive to just keep working because ta break comes at a direct personal cost to workers, who are paid not by the hour but by how much cane they cut. >> ( translated ): everyone has their own working styles. sometimes you don't want to rest, but then your body hurts. >> reporter: solidaridad has also tried to introduce a new machete, designed in australia to be more ergonomic so workerse don' to bend as low as they swing.>> translated ): we started using it the year before last and it's been a big improvement. our arms are less tired. you can feel it in your entire body.

it has let us cut more can land has effort to do so. >> (tr translated ): it', your arm feels better, your back feels better, we're having good productivity. but the blade is made of a different material and it wears t a little faster. >> reporter: that means workers have to stop more often, sometimes hourly, to sharpen their blade, which could mean losing up to a tenth of a day's earnings. for others, struggling small farmers, the cost of the new machete is also a barrier. anotheidea is crop diversification. >> this is the place where they ferment it. >> reporter: juan wright has begun a pilot program of growing cocoa, which is grown in shade forests. >> i personally think cocoa complements sugar cane. cocoa means permanent trees. it means an agricultural forest that provides jobs in coastals la a friendlier work environment. >> reporter: but switching to arw crops requires time and

money that smallrs don't have. it's one reason solidaridad's teunissen says change has come slowly in an industry long set ints ways, where a few lar sugar mills get much of theiro raw materialsmall, subsistence farmers. >> a lot of mode business practices are not readily adopted because tradition is so strong in this industr layer on top of that that it's regulated by the governments because it's so important the economy. it's not necessarily pro cessive in evee. >> reporter: meanwhile, boston university has just n a three-year study trying to further unlock the mystery of a condition that has claimed the lives of more than 25,000 central american agricultural workers over the last two decades. for the pbs newshour, i'm fred de sam lazaro in usulutan, el f:lvador. >> woodrred's reporting is a partnership with the under- told stories project at the university of st. thomas in

minnesota. >> woodruff: some have suggesteh racial, economic and political divides facing our coeytry now are deeper than have been at any point in the past four or five decades. a new port takes stock of those issues, where we stand now, and as hari sreenivasan reports, looks at some ideas for inidging those gaps. >> sreenivasan: he late '60s, after riots and unrest arnd the country, presiden lyndon johnson created a bipartis commission to assess what could be done about social injustice and economic inequality. it came to be known as the kerner commission it was controversial and concluded in february of 1968, "our nation is moving toward two societies," one black, one white, serate and unequal. this week marks the 50th anniversary of thea ommission anw update is out from the

eisenhower foundation as well as the last surviving member of the original kerner commission it lconcludes there's been r progress such as expansion of middle class for blacks and latinos and the election of many political leads including former president barack obama. but it also findthings have not improved or worsened since then. we're going to hear more about this from fred harris, co-author of new report "healing ourdi ded society" and darren walker, president of the ford foundation, focuses on a number of these issues. for the record, the foundation is a funder of the newshour. mr. harris, i want to start th you. give us a fuller picture of what you think that we have not made so much progress in. >> well, we did make progress for about a decade after the kerner report came out, but then

with automation, globalization causing jobs to disappear or tot move out central cities, with ali cal change on the conservative side that lowered taxes for the rich and for big corporations at the same time as they wer cutting spending that benefitted the middle class and poor people, we began tolow that progress. then it stopped, and since then, it's reversed. since about the last part of the 70s, we're resegregating ain. ere's worsening discrimination against african americans and latinos. and there are more poor peoe day than there were 50 years ago. poor people are poorer, and lastly, the inequality of income worsening this this country. and we want to get race and poverty back on the national agenda.

>> sreenivasan: darren walker, what do you think is responbility for that slip backwards, this resegregation, as mr. harris says?hi >> ik we made # made great progress for a number of years, but i think the growing inequality that we started to see in the 1980s has exacerbated. and so, we now have a twine challenge: allenge of addressing our historic racial bias that is rooted in our national history, in the narrative of slavery; and a new phenomenon thehenomenon of downward mobility of white americans. arfor the first time, we seeing a potential generation of white americans who a feeling insecure and anxious about their futures. the context mattd ers here, have to consider that the context that inequality and what it is doing in this country is making hopelessness and anxiety

and a feeling that america's future will not be a great future, but, in fact, our future will be one of haves and have-notes. >> sreenivasan: mr. harris, your report points out just, of course, the general statistics we're familiar with, median household income for whites is around $65,000, and r blacks it's around $39,000. but guway back, even earlier, when it comes to chidren and poverty, that we actually have now more mor american children living in poverty today. it's up to 21% now, whee it was only about 15% in 1968. >> that's right. i think you can judge a nation's priorities by looking at how they treat children. and it's just a scadal that bee have this growing child poverty in this country. you know, we know what needs to be done.no we what works. we need just to build a wheel to get it done. >> sreenivasan: mr. walker, how do you address these

different issues in a bipartisan or nrepartisan way, whee see-- in this political climate, we're seeg aetrenchment of party lines getting stronger and thicker? >> well, first ofitll, i think important to not be demoralized by the current ste because, in fact, we saw progress. it's important, beca are some who would say all of these investments were for naught. that is not true. we made tremendous strides in reducing poverty and reducing segregation in this country. today, we need to have people understand wth all, all americans-- black, white andow - are suffering from the same-- the s plague, and that is the plague of inequality. and for us to make progress, we have to show white, black, and brown americans that we are all in this togeeether. wed our leaders to bege

builders of br between communities, and to recognize that this tion needs healing, that we need to come together. >>enivasan: fred harris, how do you figure out a wayar fobased on some of the successes that we had in the pastsome of the things that did work? what were the ingredients for that for hla, and do we reinject that? >> we know jobs work. education, we know that-- onth thin we know from the past is that people have to work together. one of the great men of this country right now, i think, is e reverend william barber of north carolina, leader of a new poor people's campaign and he says we've got to quit existing and fighting inou separate silos-- labor over here and civil rights activists over here. we're all in this thing together. and he's demotrate that you could put people together around things like livable wage and around jobs and around equality, no matter what a person's zip

code or gender or race is. >>rereenivasan: dwalker, what is the source of inspiration when you look through this report? what are you seeing as kind of road map for future success? >> well what, i see, actually, success being characterized by recognizing the importance of technology in our future. technology was not mentioned in the kerner report, and today, there is nothing more important, there is no feature of our society that will desjardins determine opportunity more than technology. thenternet will be a platform for opportunity or a platform for further inequality. so we've got to focus on making sure that all americs have access to the internet, that we are ableot to replicate onhe

internet, in the digital world, the prejudice and injustice that have in the analog world. so i believe that a key unlocking in the future, and a way to address some ofthese sooshz by focusing on technology. >> sreenivasan: all darren walker of the ford foundation, fred harris, one of the original members of the uerner commission, thank yo both. >> woodruff: so important to hear. a news update. walmart is announcing iwill raise the age to buy guns and ammunition to 21. in 2015, the gianretailer stopped selling modern rifles, including the ar-15. the gun used in parkland, florida, and other mass shootings. and that's the newshour for tonight. i'm judy woodruff. join us online and again hereow tomovening. for all of us at the pbs newshour, thank you and see you soon. or >> major fundinghe pbs newshour has been provided by:

>> and with the ongoing support of these institutions ra >> this prwas made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. captioning sponsored by newshour productions, llc captioned by media access group at wgbh access.wgbh.org

milan's monumental cemetery. while there are many evocative cemeteries in europe, this one -- with its emotionalortrayals of the departed and their heavenly escorts -- in todramatic art styles from the late th and early 20th centuries -- is in a class by itself. it's a vast garden art gallery of prsud busts and grim rea roken angels and weeping widows... soldiers too young to die. acres of grief, hope, and memories.

th and we're going we're hito investigatees, ie some untold st from america's past. wes: this week, why would an american army capin have ended up with mussolini's dagger? you would need extraordinary proof to tie it to mussolini listen to this. tukufu: did the former sla who penned t letters fulfill his african dreams? powerful. gwendolyn: how uld this black box have protected americans from nucle attack? [ buzzes ] elvis costello: ♪ watchin' the detectives ♪ i get so angry when the teardrops start ♪ ♪ but he can't be wounded 'cause he's got no heart ♪ ♪ watchin' the detectives