Allies of former NSA John Bolton were shocked and dismayed when they learned that acting White House Chief of Staff Mick Mulvaney is trying to join a lawsuit filed by a former Bolton deputy Charles Kupperman to gauge if he has to comply with a House subpoena.

According to the Washington Post, team Bolton’s objection ranges from the personal to the logistical.

Bolton and Mulvaney weren’t even on speaking terms by the point that Bolton was booted from the administration, as Bolton sees the acting chief of staff as a primary player in the Ukrainian pressure campaign.

They also reportedly believe that Mulvaney is hitching his wagon to Bolton’s because of the latter’s possible loophole in testifying due to his national security-heavy role. Indeed, Mulvaney’s lawyer is already trying to make the case that his position put him in the same “national security foreign relations space” as Bolton and Kupperman.

Either way, the move is a distinct shift in Mulvaney’s approach to the subpoena. Previously, he is indicated that he would or would not testify at the pleasure of the President. He is now trying to join a group of former administration officials who say that they will defy the White House and testify if a judge gives them the go-ahead.

Per the Post, U.S. District Judge Richard Leon called for a conference call with the lawyers for Kupperman, Mulvaney and Bolton Monday afternoon to decide how to proceed.