On Twitter Friday morning, President Donald Trump accused former FBI Director James Comey of making “false statements and lies” in his congressional testimony (while also claiming that the testimony somehow delivered him “complete vindication”):

Despite so many false statements and lies, total and complete vindication...and WOW, Comey is a leaker! — Donald J. Trump (@realDonaldTrump) June 9, 2017

It’s nothing new for Trump to accuse his political enemies of lying, but what makes this a particularly serious accusation is that Comey was under oath before Congress. So if he was lying, he was committing perjury. And if found guilty under the general federal perjury statute, Comey could get a prison sentence of up to five years.

But Trump’s accusation is very difficult to believe here, for several reasons.

First, Trump himself has raised the prospect that he could have “tapes” of his conversations with Comey.

James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press! — Donald J. Trump (@realDonaldTrump) May 12, 2017

So Comey knew weeks ago that there was a possibility that his conversations with Trump were recorded. Why in the world, then, would the former FBI director go give false testimony about them, if he’s well aware there could be irrefutable evidence contradicting his claims and exposing him to prosecution? Comey’s behavior makes a whole lot more sense if, as he said, he believes any tapes will vindicate him. (“Lordy, I hope there are tapes,” he testified.)

Second, while there are certainly many cases in which administration officials have committed perjury, it makes most sense when done to protect the president or higher-ups in the administration. The hope would be that the president’s allies could shield them from prosecution or, failing that, that the president could pardon them (as in Iran-Contra).

This makes no sense in Comey’s case, because he would have to be deliberately committing perjury in order to hurt the president, knowing full well that the president’s allies would be highly motivated to try and prosecute him for even the smallest factual discrepancies.

Third, where the factual record is in dispute, Comey has evidence, and so far Trump has presented none.

Despite the president’s claim Comey told many lies, a statement from his personal lawyer Marc Kasowitz only names two specific instances in which he says Comey’s testimony is false. They are:

“The President never, in form or substance, directed or suggested that Mr. Comey stop investigating anyone, including suggesting that Mr. Comey ‘let Flynn go.’” “The President also never told Mr. Comey, ‘I need loyalty, I expect loyalty’ in form or substance.”

This contrasts with Comey’s testimony, which claims:

“[On February 14, President Trump] then said, “I hope you can see your way clear to letting this go, to letting Flynn go. He is a good guy. I hope you can let this go.” [At a dinner on January 27] the President said, “I need loyalty, I expect loyalty.” ... [Later in the dinner] he then said, “I need loyalty.”

But Trump’s lawyer presents zero actual evidence that what Comey said is false. In contrast, Comey wrote contemporaneous memos documenting each interaction that he wrote and shared with FBI leaders.

So essentially the president is accusing Comey of lying under oath about both of these topics, and in the memos he wrote and distributed months ago. If Trump has any evidence that his accusations are true, it’s nowhere to be seen. And note that while Comey’s side of the story was given under oath, Trump’s has not been.