Oops.

When Vice President Mike Pence was asked to name exactly which of President Trump’s predecessors supported his border-wall plan, the former Indiana governor came up empty.

On Friday, Trump stated: “This should have been done by all of the presidents that preceded me. And they all know it. Some of them have told me that we should have done it.”

Several media outlets, including the The Washington Post, fact-checked Trump and reached out to all four living ex-presidents—but came up empty.

A spokesman for former President George H.W. Bush declined to comment to the Post, but George W. Bush, Barack Obama, and Bill Clinton, and Jimmy Carter all denied having had such a conversation with Trump.

On the Today show Tuesday, NBC News’ White House Correspondent Hallie Jackson asked Pence directly: “Which former presidents told President Trump, as he said, that he should have built a wall? All of their representatives have denied that that was the case.”

After an audible deep sigh, Pence replied evasively. “Well, I know the president has said that that was his impression from previous administrations, previous presidents,” he said. “ I know I’ve seen clips of previous presidents talking about the importance of border security and talking about the issue of illegal immigration.”

Jackson responded: “That’s different from telling the president though, right?”

Pence said: “Look, honestly the American people want us to address this issue.”

Jackson also asked Pence if Trump will declare a national emergency in his national address Tuesday night.

He will “explain to the American people that we have a humanitarian and security crisis at our southern border,” Pence answered. “Sixty-thousand people are now attempting to come into our country illegally every month. That’s more than 2,000 every day. But what’s unique about it, Hallie, and why The Washington Post has even called it a bona fide emergency, is because the vast majority of those people now are families and unaccompanied children. And it simply is overwhelming the ability of our Customs and Border Patrol to address it.”

“The president will take those facts to the American people,” Pence continued. “He will talk about the 17,000 people with criminal records that we have apprehended at our border. He’ll explain the need not just to build a wall, which he is determined to do, but also to provide our Border Patrol with additional resources, humanitarian and medical assistance, new technology. But the Democrats need to come to the table and start negotiating.”

When Jackson asked again if Trump will declare a national emergency this week, Pence replied: “It’s something that he’s looking at and considering.”