Data and analysis from Trump's own administration drastically undercut that message, calling into question whether the situation along the U.S.-Mexican border is truly a "national emergency" as Trump said.

White House spokeswoman Sarah Sanders said Friday that Customs and Border Protection officials caught nearly 4,000 known or suspected terrorists "that came across our southern border." She repeated that on talk shows throughout the weekend, and Vice President Mike Pence used the same data point during an appearance on "Good Morning America" on Tuesday.

But in the State Department's summary of global terrorism threats published in September, analysts concluded there was "no credible evidence indicating that international terrorist groups ... sent operatives via Mexico into the United States."

Monday, NBC News reported that the number of known or suspected terrorists caught along the southern border in the first half of 2018 was about 1 percent of the Trump administration's claim. According to Customs and Border Protection data provided to Congress, the agency encountered 41 people on the Terrorist Screening Database from Oct. 1, 2017, to March 31, 2018, along the U.S.-Mexican border. Thirty-five of them  were American citizens or lawful permanent residents, and only six  were classified as non-U.S. persons.

https://www.usatoday.com/story/news/world/2019/01/08/trump-team-admits-mistakes-while-trying-tie-terrorism-southern-border/2512115002/