The Washington Post is reporting exclusively that President Trump is opposed to any current or former White House staffer testifying before Congress after the release of the Mueller report.

“In an interview with The Washington Post, Trump said that complying with congressional requests was unnecessary after the White House cooperated with special counsel Robert S. Mueller III’s probe of Russian interference and the president’s own conduct in office.”

Trump called the Congressional requests “very partisan.” It also sets up what the Post calls a “constitutional collision” between two branches of government.

Trump is trying to stop former White House counsel Don McGahn from testifying, despite the fact that he’s been subpoenaed by Congress. According to the Post, the White House will be claiming “executive privilege” but that will be tough sell since McGahn has already talked to Robert Mueller. From the Post:

“It seems to me executive privilege was waived when McGahn was permitted to give testimony and to be interviewed by special counsel Mueller,” said former Watergate prosecutor Richard Ben-Veniste. “I don’t see how the White House can assert executive privilege with something that has already been revealed. To use the Watergate expression, ‘You can’t put the toothpaste back in the tube.’”