Former White House counsel Donald McGahn is the star player in the recently released Mueller report, and now he’s the star player in what promises to be the first of plenty of high-profile battles between the White House and House Democrats over executive privilege.

Experts say the White House may have already shot itself in the foot on this one.

President Trump told The Washington Post’s Robert Costa on Tuesday that the White House plans to try to block McGahn’s testimony, and aides confirmed they may invoke executive privilege. (Trump added Wednesday: “We’re fighting all the subpoenas.”) Philip Bump has a good explainer on how this process might play out — and how the White House’s true goal may be to delay McGahn’s testimony rather than to win in court and block it.

But the battle over McGahn and executive privilege could be different from others that are likely to follow, and that’s for one significant reason: The White House may have already given up its leverage.

The White House has already effectively waived its right to executive privilege twice when it comes to McGahn. The first time came when it authorized him to speak extensively to special counsel Robert S. Mueller III — a decision that resulted in 30 hours of interviews and one that Trump has reportedly come to rue. And then it declined to assert executive privilege over redactions in the Mueller report ahead of the report’s release last week.

It didn’t have to, as Attorney General William P. Barr noted at the time.

“Because the White House voluntarily cooperated with the special counsel’s investigation, significant portions of the report contain material over which the president could have asserted privilege. And he would have been well within his rights to do so,” Barr said. But he added that Trump confirmed he wouldn’t assert executive privilege “in the interests of transparency and full disclosure to the American people.”

Trump’s interest in transparency apparently has its limits, as we’re now finding out with his decision to fight McGahn’s further testimony to the Democratic-controlled House. But experts say the dual waivers of executive privilege severely complicate any further attempt to invoke it.

“Given all of this, it seems to me that Trump cannot claim ‘backsies’ — i.e., un-waive the privilege — simply because he doesn’t like the way that things are unfolding,” said Heidi Kitrosser of the University of Minnesota Law School.

Former federal prosecutor Gene Rossi said the White House was building its case on a “fragile sand castle.”

“The waiver, however unwise, cannot be pulled back,” he said. “ ‘I consented to a search of my car and withdraw it after the police find a kilo of heroin?’ Illogical.”

Steven Schwinn, another expert on executive privilege at the John Marshall Law School, said he sees “no basis” for the executive privilege claim.

“The courts have interpreted waivers broadly,” Schwinn said. “That is, the president can ‘waive’ the privilege even without doing so explicitly.” He added that these rulings have often been based on public statements, of which Trump has made several.

Schwinn and others noted that there are other reasons the White House is unlikely to succeed, including the fact that McGahn no longer serves in the White House and thus isn’t bound by its claims. The White House is also seeking to broadly block his testimony, rather than asserting privilege on specific communications, which is generally how the privilege works. And lastly, communications that involve crime or fraud, which the Mueller report suggests is possible in this case, are not protected by it.

Mark Rozell, an executive privilege expert at George Mason University, said it was conceivable that some kind of executive privilege could be upheld — perhaps by arguing the White House’s previous waivers came on a report for which it assumed there would be greater privacy protections than there would be in public testimony. “The reasons for asserting executive privilege regarding congressional testimony may be substantively different from those pertaining to cooperating with a special counsel investigation,” Rozell said.

But he added: “Having waived privilege earlier for McGahn substantially weakens the case for coming back and asserting it to prevent his testimony.”

The question from there is whether the White House really had any choice. Politically speaking, asserting executive privilege over redactions to the Mueller report would have been dicey — as would have been preventing aides such as McGahn from cooperating with Mueller in the first place. It would have risked looking like more of a coverup.

But the White House also didn’t technically need to do either one. And reporting suggests Trump has been surprised by the content of McGahn’s extensive cooperation with Mueller — perhaps believing that McGahn would have portrayed things in a more Trump-friendly light.

In other words, the ship may have sailed when it comes to McGahn spilling key information about Trump. And the White House is going to have a difficult time bringing it back to port.