Can Donald Trump lie?
By 
This question has some legal relevance:
Federal prosecutors investigating former President Donald J. Trump’s attempts to overturn the 2020 election have questioned multiple witnesses in recent weeks — including Mr. Trump’s son-in-law, Jared Kushner — about whether Mr. Trump had privately acknowledged in the days after the 2020 election that he had lost, according to four people briefed on the matter.
The line of questioning suggests prosecutors are trying to establish whether Mr. Trump was acting with corrupt intent as he sought to remain in power — essentially that his efforts were knowingly based on a lie — evidence that could substantially bolster any case they might decide to bring against him.
Mr. Kushner testified before a grand jury at the federal courthouse in Washington last month, where he is said to have maintained that it was his impression that Mr. Trump truly believed the election was stolen, according to a person briefed on the matter.
The questioning of Mr. Kushner shows that the federal investigation being led by the special counsel Jack Smith continues to pierce the layers closest to Mr. Trump as prosecutors weigh whether to bring charges against the former president in connection with the efforts to promote baseless assertions of widespread voter fraud and block or delay congressional certification of Joseph R. Biden Jr.’s Electoral College victory.
Trump’s ability to lie is impaired by his complete indifference to any distinction between true and false statements. As Harry Frankfurt famously pointed out, attempting to lie requires a sort of minimal commitment to the concept of truth, since a liar is attempting to make a false statement, which in turn requires the liar to have sincere beliefs about the actual state of affairs. Since “sincere belief” and “Donald Trump” don’t really go together at all, it’s probably a nonsense question to ask if he “sincerely believed” he had the 2020 election stolen from him.
The other really odd thing about this situation is captured by Schmidt’s and Haberman’s last graph in the quote above. The Newspaper of Record is happy to take quasi-judicial notice of the fact that claims that the 2020 election was stolen from Trump are simply not true, in the same way that, say, the Comet Pizza conspiracy theory is not true. In other words, the fact that everybody knows those claims are not true somehow doesn’t establish that Donald Trump “knowingly” lied when he made those claims.