WASHINGTON ― President Joe Biden on Thursday blocked Republicans’ request for audio recordings of his interviews with former special counsel Robert Hur.

In a letter to the Republicans leading an impeachment inquiry against Biden, White House counsel Edward Siskel said the president had asserted executive privilege over the recordings, arguing Republicans don’t need the audio because they already have a full transcript of the interviews.

“The absence of a legitimate need for the audio recordings lays bare your likely goal ― to chop them up, distort them, and use them for partisan political purposes,” Siskel wrote to House Oversight Committee Chair James Comer (R-Ky.) and House Judiciary chair Jim Jordan (R-Ohio).

Hur declined to prosecute Biden for retaining classified documents from his time as vice president partly because Biden seemed forgetful during the interviews, leading Hur to write in his final report that the president would come off to a jury “as a sympathetic, well-meaning, elderly man with a poor memory.”

Republicans have been chasing unrelated corruption allegations against Biden in a formal impeachment inquiry since last year, but haven’t turned up credible evidence of wrongdoing by the president. Instead of impeachment articles, they seem to have settled on contempt proceedings against U.S. Attorney General Merrick Garland for refusing to hand over the Hur audio.

The transcript showed Biden struggling to place key events of his life during and after the vice presidency in a chronological sequence, with aides frequently chiming in to help. The audio would likely be useful for ongoing Republican efforts to portray the president as senile.

“Clearly President Biden and his advisors fear releasing the audio recordings of his interview because it will again reaffirm to the American people that President Biden’s mental state is in decline,” Comer said in a statement responding to the White House.

In a separate letter on Thursday to Comer and Jordan, the Justice Department said it had already given Republicans the transcript, so they know exactly what Biden said, and also that the contempt proceedings against Garland are bogus.

“It is the longstanding position of the executive branch held by administrations of both parties that an official who asserts the President’s claim of executive privilege cannot be prosecuted for criminal contempt of Congress,” assistant attorney general Carlos Felipe Uriarte wrote.

Comer and Jordan’s committees are marking up their contempt citation against Garland on Thursday, with a full House vote expected next week.

During the judiciary markup, Republicans said that since they already had the transcript, the White House might as well hand over the audio, adding that it would provide “demeanor evidence” the transcript doesn’t convey.

“That tape must be quite something if the administration, the president, has decided to assert executive privilege to keep it from the committee in the course of an impeachment inquiry,” Rep. Dan Bishop (R-N.C.).

The committee’s top Democrat, Rep. Jerry Nadler (D-N.Y.), said Republicans were hiding from “the mounting evidence that Trump is mentally incompetent to hold the office of the president.”