Trump to make his case for a border wall in address to nation Video

Transcript for Trump to make his case for a border wall in address to nation

We’re going to begin with the government shutdown, day 17 now. 800,000 federal workers and their paychecks in the balance. Other workers will not get back pay. Tonight, a growing number of TSA workers calling in sick. And tonight, the pie lot’s association now saying the shutdown is threatening safety in the air. Late today, the president revealing he now wants to deliver a primetime address from the oval office tomorrow night, calling it a national security crisis. But tonight, a key member of his team is asked about the number they’ve been putting out. They’ve been saying nearly 4,000 known or suspected terrorists come into our country illegally. You’ll see the fact-check, as it played out on Fox News. Our chief white house correspondent Jonathan Karl leading us off tonight. Reporter: Tonight, president trump is planning an all-out P.R. Blitz to make the case for his border wall. A primetime oval office address tomorrow, and on Thursday, a trip to the Mexican border. The white house insists the president has already made a big concession. The barrier, of the wall, can be of steel instead of concrete, if that helps people. It may be better. Reporter: But the Democrats say they don’t care what it’s made of. It’s not happening. The fact is a wall is an immorality. It’s not who we are as a nation. Reporter: The president repeatedly promised Mexico would pay for the wall. Now he’s demanding $5.7 billion in taxpayer money. Meanwhile, some 800,000 federal workers are not being paid. Ashaki Robinson is one of them. Ultimately, at the end of the day, there’s not a lot I can do. I’m locked out of my job. I want to go to work. I want to do my job and I’m being prevented from doing that. Reporter: With TSA workers set to miss a paycheck on Friday, the agency is preparing for workers to call in sick. There’s already been a slight increase. TSA says, though, it has had no impact on security. But tonight, in a letter to the president, the nation’s largest pilot’sdownon saying the shutdown is adversely affecting the safety, security and efficiency of our national air space system. President trump says he can relate to furloughed workers struggling to pay the bills without pay. I can relate. I’m sure that the people that are on the receiving end will make adjustments. Reporter: The white house says they are trying to mitigate the impact, announcing today that unlike past shutdowns, irs workers will be ordered to process tax refunds. And the department of housing and urban development sent a letter to more than 1,000 landlords urging them not to evict tenants. The president says the pain is work it, arguing there is a national security crisis at the southern border. Buff the white house has come under fire for exaggerating the threat. We know that roughly — nearly 4,000 known or suspected terrorists come into our country illegally, and we know that our most vulnerable point of entry is at our southern border. Wait, wait, wait. I know the statistic. I didn’t know you were going to use it. But I studied up on this. Do you know where those 4,000 people come — where they’re captured? Airports. Not always. At airports. Certainly a large number. The state department says there hasn’t been any terrorists that they’ve found coming across the southern border with Mexico. It’s by air, it’s by land and it’s by sea. It is’s all of the above. Very contentious moment playing out on Sunday morning. Jon Karl with us live from the white house. And Jon, the airline pilot’s association sending that letter to the white house, to the president, warning, as you said, that the shutdown is, quote, adversely affecting our national air space. Reporter: The pilot’s union is saying it is affecting the entire air space system. David, they say, for example, there are fewer safety inspectors on the job, and they are warning about the impact on the so-called essential employees that are required to go to work without pay, they’re warning about the personal and financial stress on those employees. David? Jon Karl leading us off. Jon, thank you.

This transcript has been automatically generated and may not be 100% accurate.