Transcript for Fact vs. Fiction: US Border Wall

??? When congress heads back to Washington after the new year, they're going to have to take up the thorny issue of immigration reform. President trump is drawing a line in the sand. Tweeting this Friday, the Democrats have been told and fully understand stand there can be no DACA without the desperately needed wall at the southern border. Translation, there will be no help for young people who were brought here illegally as children, the so called dreamers unless congress pays for the wall. In September, president trump said he would end the DACA program and give congress until March 2018 to come up with a fix. His feet this week highlights a big political battle come nlg the new year. It underscores the president's failure to live up to the campaign promise to build a wall and make Mexico pay for it. I would build great wall. And nobody builds better walls than me, believe me. Reporter: It's been a campaign hallmark. We are going to build the wall. Reporter: Back in 2016, he had this crowd in Texas fired up. Texas owns the longest stretch of the southwest border. It's where many make the crossing from Mexico to the U.S. That's Mexico right there? Yes. Reporter: I travel there had earlier this year to get a first-hand look with Texas governor Greg Abbott. Getting a bird's eye view of the Rio grande. You see how it snakes around. Goes on around. So it's one big constant "S" shape. Reporter: The U.S. Southern border stretches 1827 miles. Broken up by rivers. Deser deserts. Mountains. Canyons. Looking out of the helicopter at the dizzying terrain, we could see some barriers already in place. There's the wall. There's a gate part of it straight down over here. Reporter: But the wall trump is proposing could look very different. Early on he seemed to waffle on what form it might take. The could be S fencing. Reporter: And more recently. You need to have a great wall but it has to be see-through. We're looking at different examples. I think to be honest with you, a see-through wall would look better. Reporter: What does a see-through wall look like? Maybe like this. It allows for the officer to have visibility as to what may be posed or situated on the mex Cal can side of the Borner. Reporter: Customs and border protection is testing prototypes. Looking at how hard it is to scale, breach, or tunnel under. It's a daily force. The potential importation of terrorists or weapons of mas destruction. There is a threat that exists here every day. Reporter: In 2017, border apprehensions were at the lowest point in more than 40 years. The administration thinkings tougher deportation may deter people. Like him or love him, he's doing the right thing. A 45-year low on border crossings. That is based on the president and letting the men and women of I.C.E. Do their job. Reporter: Back in January, days into his administration, trump signed executive orders for more I.C.E. Officers and Bord border patrol agents. Hiring for trump's expect active orders won't fully kick in until at least next year. Trump seems to be ramping up his border wall push. We're calling on congress to fund the border wall, which we're getting very close to. Reporter: How close are we really? Trump needs to get congress on board. Likely a tough sell with Democrats. I made it so, so clear to the president there is not going to be a wall in appropriations process or in others. At one point he said, go easy on the wall. I said no.

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