the newshour tonight, students return to the florida high school whfte a shooting 7 dead, as president trump meets with both democratic and republican members of congress mmunications director, h teres. hicks, mr.mp's longest serving aide, announces she will resign. then, securing america's ballot box-- with midterm elections around the corner, fears grow of further russian meddling in the nation's democracy. and, decoding north korea's nuclear abilities-- how researchers are dissecting the regime's propaganda for cltis inside its 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 released and we try to, what we call, geolocate them. >> woodruff: all that and more on tonight's pbs newshour. >> major funng for the pbs newshour has been provided by: >> the lemelson foundation. committed to improving lives through invention. the u.s. and developing countries. on the web at lemelson.org.

>> supported by the john d. and catherine t. macarthur foundationui committed toing a more just, verdant and peaceful world. more information at macfound.org >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs statn from viewers like you. thank you. >> woodruff: it's been since a gunman killed 17 people at a high school in parkland, florida. today, the school reopened, asta continued in washington on what to do about guns. john yang has our report. >> yang: students returned to marjory stoneman douglas high f hool classrooms this morning, amid reminders oe valentine's day killings. >> we're never going to be back to gormal, but it's going to

us in the right direction again. >> yang: makeshift memorials re piled high with flowers. some brought signs of encouragement. there was a heavy policeen pr. >> oh, wow there are a lot of police. oh my goodnessyeah that is a lot. n >> yang: therly 3,300 students began the day with fourth perd, the classes that were underway when the shooting started two weeks ago today. >> we start the day in the class where the event took place, so ike gonna be a little sad 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 watcd 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 the rest of this year with all this significant presence and efforts to strengthen and

fortify it. erit's still the scene of my daughter, unfortunately, was murdered. g: a teacher posted a picture of a therapy dog in her classroom.de many stus say they would keep fighting for stricter gun control laws. >> we're still around, we're kicking it, we're still trying to send a message. don't forget about us, because we can't forget about those who we lost. >> yang: the school reopened as a major gun retailer, dick's sporting goods, announced it's not iting for new legislatio c.e.o. edward stack said the company will stop selling assault-style riflesnd will not sell any gun to anyone under 21. >> we were so disturbed and saddened by what happenewe felt that we really needed to do something.ve we didthing that the law required and still he was able to buy a gun. >> yang: the 19-year-old shooting suspect, nikolas cruz, legally purchased a gun from dick's last fall, but not the a.r.-15 he allegedly used in the shooting.

at the white house, meesident trumwith a bipartisan group of lawmakers to talk about gun control legislation. >> as we continue to mournhe loss of so many precious young lives, we're determined to turn our grief into action. >> yang: mr. trump backed better background checks for gun purchases, including privatee sales, like th gun shows, and arming teachers and other e hool workers. >> i really beli will prevent from ever happening. they are cowards, they're notng going in knohey're gonna come out dead. >> yang: in some of the worst school shootings, though, like oolumbine, virginia tech and sandy hook, the rs killed themselves. and the president underscored his differences with the powerful national rifle association on raising the age for buying assault-style weapons and saying that guns should have been preemptively taken away om cruz whether "they had a right to or not." he also said a bill to pass conceal and carry laws across lines should not be part

of a bipartisan bill. >> i'm a big fan of the n.r.a., these are great patriots, theyou love ourry, but that doesn't mean i have to agree with them >> yang: democratic senator asris murphy of connecticut told mr. trump that psing legislation required esidential leadership. >> mr. president, it's going to have to be you who brings the republans to the table on this because right now the gun lobby would stop it in its tracks. >> yang:s the president and lawmakers seek common ground in hopes of trying totop the loss of life that the studentr in e pbs newshour, i'm john yang. >> woodruff: in a related development, police in dalton, georgia arrested a high schoolte teacher he barricaded himself in an empty classroom, and fired a handgun once. no one was hit, but one student sprained an ankle runns g. ther word on the teacher's attive. white house communns director hope hicks announcedy toe 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 inne office andf the president's longest-serving advisers. hicks' announcement comes a day after she testified before the house intelligence committee as part of its ongoing instigation into russian interference in the 2016 presidential election. ashley parker is a white house reporter for the "washington post."th ashleyk you for joining us. so, what is known about why hope cks is doing this? >> so, i first should underscore that this is an incredibly stunning development. there was a sense that eved in a chaotic multuous white house, that there was one person who would be with president trump rough 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 testimony on capitol hill. and she has told people that she

basilly wants to spend-- be closer to home, to her family in connecticut, that three years focused solely on one thing and working in this incr high-pressure and high-intensity environment just talks a toll on anyone and she realized it was her time to move on. i do have to say, this comes as she, herself, was under a lot of personal stress.th e was not just that testimony. she had been romantically linkee to staff sry rob porter, who was forced out of the white house amid allegations of domestic abuse, and more broadly, right now, the mueller probe is intensifying, and it feels like it's creeping closer to the west wing and the oval office. hope hicks is someone who literally sits outside the oval office, d is intimately involved in everything. if there is someone who wouldf sortow every little bit and piece of what is said and done in that white hou is hope hicks. >> woodruff: she sits right next to the president, has t t

closest offihis. and, ashlee, there was reporting onyesterday after her test that she had told the committee members that she did sometimes tell what she called "white lies" for the presiden there's been a lot of speculation about that and whether that had some effect on this. >> that's right. , and again, she has toldop -- she had told some people about this decision before her testimonywhere she mentioned the white lies, and she claims that that-- the russia investigation in general, has nothing to do th this. but you have to recognize that, again, more than anyone in this white house, hope is in an siincredibly precarious potion because she was often called upon, by her own admission, to sort of fib for the president, and, you know, maybe engage some some misdirection. and there's no crime, as we unfortunately all know, with lying to the media.nn but you lie under oath to congressional investigators and you certainly cannot lie when you speak to a special counsel.j >> woodruff: at quickly,

ashley, you pointed out she's been at the president's side for a long time. we said longest serving aide. and this does follow a number of other top advisers to the president who have left just in the firs>>year. hat's another incredibly important point. and this is a president who ruit the house like a family business, and he likes to surround himself with d miliar faces ople 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 post," thanks very much. >> thank you. >> wdruff: in the day's othe news, president trump got into a new dispute with his attorney general, jeff sessions, over the russia investigation. sessions had announced his inspector general will look into whether the f.b.i. abused its surveillance powers. this morning, mr. trump tweeted the review "will take forever." and, he asked: "why not use justice department lawyers? disgraceful!" sessions answered in a statement that said: "i will continue to

discharge my duties with integrity and honor." meanwhile, former trump campaign chair paul manafort pleaded not guilty today to updated federal charges in the russia investigation. they involve money laundering and acting as an unregistered foreign agent.e the jut 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, russiaid prt vladimir putin claimed some civilians did get out of eastern ghou, despite rebel tacks. >> ( translated there is constant shelling from there. on some days there are up to 50 or 80 rocket and morrikes. we have managed to get out quite a big group of those who wanted to leave from there. but the second group that was prepared could not leave because

the militants just did not give them an opportunity to do that. >> woodruff: syrian war monitors said they could not confirm that anyone has been evacuated from eastern ghouta. the government of afghanistan offered today to recognize the taliban as a lawful political 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 have the decision to make. accept peace, accept it with honor and come together, so we can make this country safe andre sewhich is the heritage of our sacrifices, jihad and our blood. >> woodruff:he taliban had no immediate response to the offer. back in this country, the u. supreme court will decide a case that focuses on what to wear when voting. justices heard arguments today on a minnesota law that bars most polit at the polls.atthing

a number of have similar laws, but minnesota's is broader than most. i teacheat least two west virginia counties are refusing to go back to work tomorrow, after a five-day strike. that's despite the governor's offer to raise pay five percent. most teachers are expected back tomorrow, but some are holding out folower health insurance premiums. the u.s. olympic committee announced a shakeup today, amid the scandal over sexual abuse of young gymnasts. c.e.o. scott blackmun said he's resigng after being diagnosed with prostate cancer. the u.s.o.c. is investigating how blackmun and others handled the abusissue. on wall street, worries about higher interest rates triggered another sell-off. the dow jones industrial average tlost 380 points to close 25,029. the nasdaq fell 57 points, and the s&p 500 dropped . both the dow and the s&p had

their worst months in two years. and, president trump andre co paid tribute to billy graham today, as his casket arrived at the u.s. capitol rotunda. the late evangelist is just the fourth private citizen to lie in honor there. the president, lawmakers, and hundreds of others turned out. senate majority leader mitch whconnell eulogized the ma came to be known as "america's >>pastor." he man we recognize today shared the gospel with people face-to-face than anyone else in history. tss clear voice thundered through packed tstadiums, auditoriums, parks and plazas the world over. his warmth and graciousness lit up living rooms and touched hundreds of millions of hearts. >> woodruff: billy graham died last week at 99.

he will lie in honor through tomorrow. his funeral will be friday in charlotte, north carolina. still to come on the newshour: can 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. >> woo homeland security is pushing otback at reports that say migistration systems in seven states were compd by russia before the 2016 esidential election. the threat they posed has been confirmed by the heads of all u.s. intelligence agencies.r yey, the leader of the national security agency testified before the 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 center for election innovation and research, and denise merrill. she's the secretary of state in tennecticut. she oversees the s elections. welcome to both of you to the newshour. david becker, to you, first, in dsum, what did the russiato election systems in this country in 2016? >> well what, we know from testimony from the ielligence community and elsewhere is that they attempted to probe orcan several state systems, probably most notably, voter registration database systems. almost all of those scans and probes were unsuccessful. there was one instance in illinois where they successfully accessed voter data, about 70,000 records or so, in june and july of 2016, but no records were altered or deleted. we also know from the intelligence community and from multiple investigations all around the country, that theresu were nessful efforts to

change votes or change vote totals or tallies throughout the united states. >> woodruff: dene 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 russian i.p. addresses. again, our firewalls and our systems held. they were trying to get into our voter registration database,wh h i think is similar to what happened in the other states. i think the good news th didn't get in. hed i think that's pretty much true in all the states with that one exception that david mentions. >> woodruff: and denise merrill, staying with you, what evidence or belief do you have right nothat that i ever continuing to try to do that in this 2018 midterm election year? >> well, i do think the threat of russian interference in our election is real. i've become convinced of that, not only by what has happed, but by what could happen. i think we're all on alert now

that there could be other attempts. thhonestly think that the biggest goal tha 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 vulnerable? >> well, the more we rely upon technology, all technology has some vulnerabilities'so it. and thhy it's fortunate have systems in place to double check the technology. so, for instance, paper ballots, auditable ballots that can be auted after the election i very, very important. y e good news is 75% to 8% of americans currente on paper, and that number is increasing as virginia has moved to a paper. pennsylvania is about to move to all paper. and about 17 states are considering ways to improve their audits. systems like that are ve, very important to make sure we can trust electronic machines that are counting our votes. atbut the good news smost are doing it, and even more states are moving in that direction. >> woodruff: and david barker,

just to ify, this is a state-by-state situation, right? there's no federal election overlay, as i understand it. >> that's right. and a major federal election, wt not only dold one election or 50 elections. we actually hold about nearly 10,000 elections because all of theon local jurisdicare actually running the elections. that does give us some protection against hacng because it's difficult to hack into 8,000 to 10,000 different systems. but we do have to be vigilant. secretary merrill is exactly right-- russia is trying to do this. the intelligence community is unn.imous in that determinat and their goal is probably not actually to change vote totals but, rather, to get us all to lose confidence in our own election system. so it's very important that we all understand that the election ofndcials, like secretary me 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, denismerrill, what is

that connecticut needs? what do you need in your state to be sure that there's not interference this year? andhow much support, what k 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 hygne, the kinds of firewalls, i guess you'd call them, against thisth sort og. but we are getting help now from the department of homeland security. they do have resources that can help, not enough of them, and not enough to go around. so ihink we could use more o that. some states are much further along than others, as we. and, of course,, you know, there are some federal laws at came into play after the 2000 election, which was the last time this sort of thincame up with the hanging chads, and so forth. and the "help america vote" act did provide much of the funding thr you're seeing in place the current election systems. they're getting older. so at some point, we should look at replacing some of that.

>> woodruff: and i think what we've seen in the news in the q last few days stions, concerns about whether the federal government is taking this seriously enough, doing enough to help the states. and i just hear you say, denise merrill, that you're not getting all the help you need. >> no. and i'm not sure it's d.h.s.' fault. i think they are trying to be helpful, but they have limited resources. and i was rather surprised, but not entirely surprised, to learn of the statements by the f.b.i. director, i guess it was yesterday or today, that he did not have direct authority to act to preve some of this. so i am concerned about that.th i thinstate officials, election officials all over the country are on alert.il we're ready,ng, and able to help. we're very familiar with this ri assessment kind of thin we've been doi it for years in ections. this is just a new venue and a new kind of a threat. and i'm waiting for a direction from them. i think they could be immensely

helpful. we're doing better. we have a great communication system we're developing but they quuld do more for us, yes. >> woodruff: verkly, in just a few saturday, david becker, what would be most important to help states aroundlet country harden up their systems sore they're not vulnerable? >> well, there's unprecedented cooperation between the federal government and the states andth local election officials but the one thing they really need right now is resources and funding. there's no finish line in cyber-security. when you improve cyber-security, the bad guys get better, too. there need to be better funding streams, perhaps at the state level and congress. >> woodruff: david becker with the federal center for electiona inoovati 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 taken us on a tour of what's publicly knout north korea's nuclear weapons program. a in the thi final part of his series, miles looks at how those bombs might be delered. tonight, on the leading edge of science, the sleuths searching through open source clues to north korea's fast-developing miile program. >> reporter: north korean misses are flying much farth and much more 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, sensors and satellites that track the missiles in real 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 usually find the preaunch location using photographs. >> reporter: lewis is director of the east asian nonproliferation program at the middlebury institutel f internatioudies at monterey. 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 te all the pictures that they released and we try to, what we call, geolocate theme wele to see where the launch occurred, and we are even able to tell where kim jong un is standing when he watch >> reporter: lewis and his team are dialed into a global networs of armchair an on a similar mission. marco langbroek is aime amateur satellite tracker and blogger based in the netherlands. he>> the end result of all measurements is that you have a very nice calibration of what directions is where on the horizon. >> reporr: he gave me a fascinating glimpse into a realm that sounds liken oxymoron;" open-source spying." the north koreans released these

images of their last and largest missile test of a hwasg 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 >> 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 13d his team. it all began with econd video showing kim jong-un's father and predecessor, kim jong-il, in a building with some no dong missiles in the early 2000s. >> ihas these very unusual windows along the back and the side awe in the roof. hought, "if we know where the windows are then we canin model thde of the building, use that to model the outside of the building. and then, if we know

approximately where to look, we cafind this thing in a satellite photograph. >> reporter: they made a 3-d model of the building and th missile carrying truck based on the images, and homed in on their quarry. >> and so, there it is. you could see it's exactly the building that we imagined. and yocan see the reason that they added the big skylight was precisely so tt the vehicle would fit in and that they could lift the missile all the way up. >> reporter: similar techniques can also give outsiders an inkling on how succeful a missile test is. >> what you 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 tractory of the missile. >> you can compare whether whatm theynt to do with their launch actually matches what the rocket really did. >> reporter: he uses software that corrects the distortions caused by the perspective of tha ca he compares the red line on the map with trajectories of the test released by western military sources.of

doing alhis 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 oe well, which of cours important in terwhen you are going to use them in a real war situation. >> reporter: so far, north koreans haveested their large missiles on highly elliptical suborbital flights. flatten out the ar15and a hwasoncan reach anyco location in thinental u.s. >> this is a model of the hwasong-12. this is the missile that was being lifted by the >> reporter: lewis also measures the prowess of north korean missiles by timing the eaceleration off the launch pad. >> if you know how the thing is and how quickly it is being pushed, you know how much power iseing used to push it. so, we've been able to estimate the strength of the north koreae enand as it turns out, we get exactly the same number as the leed u.s. intelligence 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.by >> and sodeling the building and the missile and the crane, we were able to figure out how far the arm was extended, the angle he 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, s e of the things we discovered is that north koressiles were more advanced than we thought. the missile itself was stillmu very strong bu lighter than we expected. >> reporter: lewis believes the north koreans have the technology and knowledge to mill so called "isogrid" pieces like this. they are as strong as a solid piece of metalbut much lighter. >> this is hard to do unless you have modern computer numerically controlled machine tools and that's precisely what kim jong- un was showing us in that building. it was that they have the capability to this sort of thing. >> reporter: but they also have

mathe capability to doctors, lewis discovered kim jong-un's d.rs are often photoshoppe and remember that starfieldo mangbroek analyzed? a later image from the same vaage point, of the launch itself, shows stars that would be behind the camera. >> the star backgrounds are dramatically different. because here it shows orion and here it shpart of andromeda with andromeda galaxy over here, and these are complete different parts of the sky. this is in the south-southwest and this actually in the northwest. so that's not possible. they should show the sky t background by 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 ofat course, more beautiful 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 were the north koreans one thing i might do is just stop all of is propaganda altogether.

but then, they lose the deterrent value, right? they lose the threat because if you can't see it, then you don'n it's real. so, i think we're both locked in thisame where they want to tell us some things and notd others, anour job is to figure out what those other thingthey don't want to tell us are. u ib reporter:il technology made all this possle, this job fell in the realm theal professipies, shared only with policy makers that have a security clearances. >> this waactually my very first trip. >> reporter: nuclear physicist sig hecker is one of those ople. he ran the los alamos national laboratory from 1986 through 1997. he supports the open source sleuthing. >> the open-sour informs the public and what's actually important, of course when u do open-source, you do get more peeyes on the problem, morle to think about it, more people who think in ways that perhaps and north korea might think that then what we have in our government.

>> reporter: in fact, 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 any american city. for the pbs newshour, i'm miles. o'brou >> woodruff: y can watch 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'kesugar cane w. plus, our racial divide: a new look at race in the u.s., 50

years after a senal report. but first, staying with the topic of north korea, since the start of the year, tensis have lowered on the korean peninsula: in the past few weeks, north koreans participated in the olympics in south korea. kim jong-un's sister attended the games, and gave the president of south kea a letter from her brother, inviting him to north korea. 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 now between north and south korea, and with the south's american ally? for that we turn to moon chung- in. he is senior foreign policy and unification advisor to south korea's president. . moon, welcome to the newshour. the trump administration describes its policy toward rth korea as "maximum pressure." you said yestelday that it

she instead "maximum prudence." why? what did yi mean? >> whaid is our president is taking maximum prudence in dealg with north korea and i dealing with the united states. we are hoping that ourdent would turn maximum pressure into some kind of dialogue and negotiation through prudent policy. >> woodruff: what do you thinkth the chances ar 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. >> woodruff: if there were to be u.s.-north korea talks, some denuclearization be the main

focus of those talks? >> sure. because denuclearization ofh norea must be the goal of the united states and south korea. >>oodruff: i ask because, clearly, there are human rights issues, so many other issues, that could be discussed between >> no, i think it is better to prioritize. right now the most 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 will regard is as a hostile act by the united states. therefore, it is better n r us to focuse nuclear and missile issues, then follow up with human rights and democracy, when and if there is some degree of confidenc trust building between the u.s. and north korea. >>oodruff: should there be any preconditions before there were talks between north korea

and want united states >> i personally believe that it is better to have a talk without any precondition. because time is on nobody's side. >> woodruff: and does the u.s. agree with you about that? >> i hope that they would come up that kind of colusion. >> woodruff: how often is your government talking to the north korean government? >> on the occasion of the pyeongchang olympics, south korea was able to restore all chables of communication with e,rth korea. thereft would be much easier for us to talk with north korea now and in the future. but up until the end of december last year, there was no channels of communication. there was a big change. >> woodruff: there is, clearly, discussion about military exercises that the u.s. and south korea are scheduled t cat in the coming few months. the north koreans say they,on obviously, like these

exercises. they feel threatened by them. could those exercises be delayed? do u.s. and south korea agree on whether to go ahead with them, the timing of them? >>ulhe american embassy in s made it ry clear yesterday there would be no more delay of the schedule of our joint military exercise. but, hower, as to the joint military training, which is different from exercise, there could be some room for adjustment. but i cannot tell you what would be the future prospect. >> 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 joint military exercise. >> woodruff: how worried are people of south korea by a

strike by north korea, either a deliberate strike or a mistake? >> we are very fearful of the north korean threat. north korea has now nuclear weapons capability. north korea has deployed more than 8,000 long-range artillery pieces. they can in the seoul metropolitan area. t the dilemma s: if we show eanic, then we become the hostage of north kn the tactical move. that's why we in south korea ernd to be much more calm the noh korean threat. it is ironic to note that america is f away from north korea, but america is most concerned, and jap still quite far away from north korea, but japan is second in terms of a threat perception.bu south korea, even though under the immediate north korea, said we show calm behavi. i don't know whether it's good or not.

but that is the way we should handle north korea. >> woodruff: what about a esstrike by want united st # on north korea? how much does your country thin and woout that? >> yeah, we are very muchrr d about american unilateral military action 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 korea cannot really tolerate american military action on north korea. that is why we have been pushing for the idea of diplomaticso tion of north korea nuclear problem.f: >> woodrufell, mr. moon chung-in, we thank you very much for coming in todaalk with us >> thank you. >> woodrf: in many central american communities, a mysterious disease has affected

fa workers. salvadorspecial correspondent fred de sam lazaro focuses on workers who arcaught in the middle of trying to e out a living while maintaining their health. this report is part of fred's series "agents for change." >> reporter: the cutters begin early, trying to sneak a couple of hours before the tropical sun begins to scorch the sugar ce fields. it's dirty, brutal work that requires the stana of the young and physically fit, the exertion likened to running a half marathon every day. but 20 years ago, doctors began noticing an alarming increase in the number of these young workers across central ameca who were coming into hospitals with a mysterious, ultimately fatal kidney ailment. dr. ramon garcia is a kidney specialist in el salvador's capital, san salvador.

ve>> seven to eight deaths day in this small country. it's 10 to 12 times more than the expected death rate. this is a silent massacre. >> reporter: adr. garcia and others began to investigate, they discovered that on some farms, nearly one-fifth of sugar cane workers were suffering from nronic kidney disease eve though they had none of fe usual risktors such as high blood pressure and diabetes. jose monjares has been a cane cutt most of his adult life the small coastal region that is the sease's epicenter. his father and uncle died from it. he got his diagnosis seven yrs ago. >> ( translated ): it came on very suddenly: back pain, fever, vomiting. >> reporter: the illness forced him to stop the grueng working as a cutter so he now works as a field assiant.

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 diet. because if i don't, i'll have to get dialysis and that just means death. >> reporter: ramon aguilar, who heads a cooperative of small farmers in the region, says at least 10 of his members died last year from kidney disease. >> ( translated ): there may have been others who died who weren't diagnosed. re in el salvador, many people don't want to recognize this disease and exat an epidemic ts. >> reporter: dr. garcia and other researers, including a am from boston university, have conducted several studies trying to determine the cause. initially pesticides considered a likely culprit, but there was no explanation whydi these chemical't have a similar impact in other places they are sprayed, including the united states. dr. garcia says one thing they believe may be a contributing factor: the severe dehydration

of the workers, which prevents the kidneys from functioning fully. >> it's too hot, simply too hot. you cannot drink enough water a me pace that you are losing it in sweat. we're not sure if this is the e ly cause or a mix of causes that put together oducing the disease. >> reporter: as researchers scramble to find the root cause of the disease, some groupare focusing on improving working conditions. some regions of the world have mechanized cane harvesting. it lowers the financial cost but would create a social one here, says sebastian teunissen of th netherlands-based group solidaridad. >> something has to change. it could be mechanization. it could be that farmers work together in cooperatives so they make effective use of the land. at means surplus labor. one of the issues really isla

where is thar going to go in the coming decades? >> reporr: his group and hers 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: st 8% of the sugar processed here comes from company land. most comes from small farmers, 2,000 of them, says owner juan wright. >> just to convie 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 incentive to just keep working because taking a 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 n'eir own working styles. sometimes you dowant 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 workers n't need to bend as low as they swing. >> ( translated ): we started using it the year before last and it's been a big imouovement. arms are less tired. you can feel it in your entire body.s it has lett more cane and have less effort to do so. >): it's true,d ur arm feels better, your back feels better, we're having good productivity. but the blade is made of a different material and it wears out a little faster. r: 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, ruggling small farmers, the cost of the new chete is also a barrier. another idea is crop diversification. >> this is the place where they ferment it.

ra reporter: juan wright has begun a pilot prof 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 coastal lands at a friendlier work environment. >> reporter: but switching to new crops requires time anll money that sarmers don't have. it's one reason soliridad's teunissen says change has come slowly in an industry long set in its ways, where a few large sugar mills get much of their al from small, subsistence farmers. >> a lot of modern business practices are not readily adopted because tradition is so strong in this indus layer on top of that that it's tsregulated by the governm because it's so important to the economy.es it's not nrily progressive in every case. >> reporter: meanwhile, bostoner unty has just begun a

three-year study trying to further unlock the mystery of a condion that has claimed the lives of more than 25,000 central american agricultural workers over the last two decade for the pbs newshour, i'm fred de sam lazaro in usulutan, el salvador. >> woodruff: fred's reporting is a partnersp with the under- told stories project at the university of st. thomas in minnesota. >> woodruff:ome have suggested the racial, economic and political divides facing our country now are deeper than they have been at any point in the past four or five decades. a new report takes stock of those issues, where we stand now, and as hari sreenivasan reports, looks at some ideas for bridging those gaps. >> sreenivasan: in the late '60s, after riots and unrest arou the country, president lyndon johnson created a

bipartisan 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 inbr ry of 1968, "our nation is moving toward two societies," one black, one white, separated equal. this week marks the 50th anniversary of the commission and a new update is out from the l senhower foundation as w the last surviving member of the eniginal kerner commission it concludes there's eal progress such as expansion of middle class for blacks and latinos and the election of many litical leaders includin former president barack obama. but it alsfinds things have not improved or worsened since then. we're going to hear more about this from fred harris, co-author of new report "healing our divided society" and darren walker, president of the ford

foundation, focuseon a number of these issues. for the record, the foundation is a funder of the newshour. mr. harris, i want to start with 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 theo with autom globalization causing jobs to disappear or to move out of the central cities, thth a political change on the conservative sid lowered taxes for the rich and for big e rporations at the same t they were cutting spending that benefitted the middle class and poor people, we began to slow that progress. then it stopped, and since then, st's reversed. since about the art of the 70s, we're resegregating again. there's worsening discrimination

against african americans and latinos. and there are more poor people today than there were years ago. poor people are poorer, and lastly, the inequalityf income is 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 responsibility forhat slip backwards, this resegregation, as mr. harris says? >> i think 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 acerbated. and so, we now have a twin challenge: the challenge of addressing our historic racial bias that is rooted in our h nationtory, in the narrative of slavery; and a new phenomenon the phenomenon of downward mobility of white americans.fo

the first time, we are seeing a potential generation of white americans who are feeling secure and anxious about their futures. the context matters here, and we 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, t, in fact, our future will be one of haves and have-notes. >> sreenivasan: mr. harris, your rort points out just, of course, the general statistiar we're famiith, median household income for whites is around $65,000, and for blacks it's around $39,000. but guway back, even earlier, when icomes to children and poverty, that we actually have now more american children living in poverty today. it's up to 21% now, where it was

only about 15% in 1968. >> that's right. g think you can judge a nation's priorities by look how they treat children. and it's just a scandal that bee have this growing child poverty wh this country. you know, we kno needs to be done. we know 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 nonpartisan way, where we see-- in this political climate, we're seeing a retrenchment of party lines getting stronger and thicker?>> ell, first of all, i think it's important to not be demoralized by the current state because, in fact, we saw progress. it's important, because there oare some who would say a these investments were for naught. that is not true. we madtremendous strides in reducing poverty and reducing segregation in ts country.

today, we need to haveeople understand that we all, all americans-- black, white and brown-- are suffering from the same-- the same plague, and thas he plague of inequality. and for us to make progress, we have to show white, black, and brown americans that we are all in this together. we need our leaders to be builders of bridges between communities, and to recognize that this nation needs healing, that we need to come together. >> sreenivasan: fred harris, how do you figure out a way foard based on some of the successes that we had in the past, some of the things that d work? what were the ingredients for that formula, and how do we reinject that? >> wknow jobs work. education, we know that-- one thing that we know from the past is that people have to work together. one of the great men of thisgh country now, i think, is the reverend william barber of

north carolina, leader of a new poor people's campaign. and he says we've got to quit f existing ahting in our separate silos-- labor over here and civil ghts activists over here. we're all in this thing together. and he's demonstrate that you could t people together around things like livable wage and around jobs d around equality, no matter what a person's zip code or gender or ce is. >> sreenivasan: darren walwhr, is the source of inspiration when you look through this report? what are you seeing as kind of a 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,nd today, there is nothing more important, there is no feature of our society that will desjardins determine opportunity more than

technology. the internet will be a platform for opportunity or a platform for further inequality. so we've got to focus on making sure that all americans have access to the internet, that we are able to not replicate on the internet, in the digital world, the prejudice and injustice that we have in the analog world. so i believe that a key unlocking in the future, and a way to address some of these sooshz by focusing on technology. >> sreenivasan: all right darren walker the ford foundation, fred harris, one of the original members of the kerner commission, thank you both. >> woodruff: so important to hear. a news update. walmart is announcing it will raise the age to buy gs and ammunition to 21. in 2015, the giant retailer stopped selling modern rifles,

including the ar-15. the gun us in parkland, florida, and other mass shootings. and that's the newshour for tonight. i'm judy woodruff. join us online and again here tomorrow evening. for all of us at the pbs newshour, thank you and see you soon. >> major funding for the pbs newshour has been provided by: or and with the ongoing su of these institutions >> this program was made by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. on captioning spsored by newshour productions, llc

captioned by media access group at wgbh access.wgbh.org

♪ >> by last count, there are more than 30,000 hot pot restaurants in chengdu, 30,000. there are only 24,000 restaurants in total in entire new york city. sore we talking about an addiction or obsession? st how much do the people in chengdu love their hot pot, and why? pull up a chair. stick around, and you'll find out next on "yan can cook." ♪ ♪ ♪ ♪