(WASHINGTON) — President Donald Trump’s lawyers composed a secret 20-page letter to special counsel Robert Mueller to assert that he cannot be forced to testify while arguing that he could not have committed obstruction because he has absolute authority over all federal investigations.

The existence of the letter, which was first reported and posted by The New York Times on Saturday, was a bold assertion of presidential power and another front on which Trump’s lawyers have argued that the president can’t be subpoenaed in the special counsel’s ongoing investigation into Russian meddling in the 2016 election.

The letter is dated January 29 and addressed to Mueller from John Dowd, one of Trump’s lawyers at the time who has since resigned from the legal team. In the letter, the Trump’s lawyers argue that a charge of illegal obstruction is moot because the Constitution empowers the president to, “if he wished, terminate the inquiry, or even exercise his power to pardon.”

Trump weighed in on Saturday on Twitter, asking “Is the Special Counsel/Justice Department leaking my lawyers letters to the Fake News Media?” He added: “When will this very expensive Witch Hunt Hoax ever end? So bad for our Country.”

Mueller has requested an interview with the president to determine whether he had criminal intent to obstruct the investigation into his associates’ possible links to Russia’s election interference. Trump had previously signaled…