Homeland Security Secretary Kirstjen Nielsen, second from right, speaks Wednesday. (Susan Walsh/AP)

The Trump administration’s repeated claims that terrorists are crossing the U.S.-Mexico border has been fact-checked and debunked into the ground at this point. White House press secretary Sarah Sanders even acknowledged her error in using such a statistic Wednesday. Vice President Pence’s office has conceded he misused the same stat. And President Trump appeared to abandon the talking point in his prime-time address on Tuesday night.

Alas, this is the falsehood that just won’t go away, thanks to complicity from top Trump Cabinet officials.

Appearing on Sean Hannity’s Fox News show on Wednesday night, Homeland Security Secretary Kirstjen Nielsen agreed with Hannity’s premise that terrorists were, in fact, using the southern border.

Here’s the exchange (emphasis added):

HANNITY: For some people the media’s been like a numbers game. We do know Americans die. We do know, I’d argue, probably 98 percent of people that want to come here want hope, opportunity, liberty, freedom and all the things we may even take for granted ourselves. But it is the 2 percent that I worry about that are part of the -- the gangs, the drug cartels. The 2 percent maybe you have talked about, but you can’t give numbers. There are instances that you can confirm, that you know of terrorists that have tried to cross our southern border, and we’ve apprehended them. 

NIELSEN: Yes, Sean. And we have talked about the thousands -- the thousands of terror watchlist individuals who traveled through our hemisphere last year. To pretend there’s not a danger on an unsecure border on an open border is -- it’s just ridiculous. It belies common sense. But it’s not just the security crisis that the president and the vice president continue to draw the American public’s attention to; it’s the humanitarian crisis.

“No, Sean.” The answer is “No, Sean.”

This blog has been part of the almost-incessant fact-checking of this claim, but I’ll rehash it briefly here. The State Department said clearly in mid-2017 that there was “no credible information that any member of a terrorist group has traveled through Mexico to gain access to the United States.” It updated the language in September — four months ago — to say, “At year’s end there was no credible evidence indicating that international terrorist groups have established bases in Mexico, worked with Mexican drug cartels, or sent operatives via Mexico into the United States. The U.S. southern border remains vulnerable to potential terrorist transit, although terrorist groups likely seek other means of trying to enter the United States.”

We did learn this week that there were a handful of known or suspected terrorists that were apprehended at the border in 2018 — around a dozen, according to reports — but that’s not “terrorists.” That’s people whose names matched the terror watch list, a list that almost always flags people who aren’t actually terrorists. In fact, according to NBC’s reporting, there were many more people apprehended using the terror watch list on the northern border. There has been no official government reporting that anybody apprehended at the Mexican border was actually a terrorist. And you can bet if such evidence existed, it would have been circulated widely at this point by the administration.

Nielsen herself has said such information is too “sensitive” to share, but here she was on a friendly TV show on Wednesday night confirming Hannity’s premise that actual terrorists had, in fact, been apprehended at the border.

It’s possible she didn’t mean to confirm that premise and was just being overly agreeable. Maybe she thought Hannity meant “known or suspected.” But this specific claim is something that has been a huge focus of the government shutdown and border wall debates in recent days. Nielsen herself issued a lengthy defense of the danger terrorists pose at the border on Tuesday, including issuing a “MYTH/FACT” sheet about it. If she’s so concerned about myths and facts, you’d think she’d be more careful about spreading a myth.

But she’s not even the first Cabinet official to appear on Hannity’s show in the last week who seemed to confirm Hannity’s premise. Here’s Secretary of State Mike Pompeo last week failing to correct Hannity’s use of the false stat Sanders, Pence and others have used:

POMPEO: Border security is an important part of American sovereignty and keeping Americans safe. There is a center (ph) role to make sure that we know who’s coming in and what is coming into our country, and President Trump is doing the right thing in making sure we understand what’s moving across that border.  And we do so with enough border security, so we have confidence and we can do this on behalf of the American people.

HANNITY: We’ve been able to apprehend 3,700 people that we’ve identified as having ties to terror?  

POMPEO: There’s lots of risks associated. The narcotics risk itself has enormous implications for people inside the United States. There are lots of things that come across that southern border that we need to get control of, and President Trump is determined to make that happen.  It includes the risk that we have terrorists come across that border.

This conversation was clearly about the border, when Hannity busted out the 3,700 number — which is actually for all apprehensions, which are almost all at airports. Pompeo said nothing.

It’s extremely difficult to dismiss all this as a coincidence.