Attorney General Jeff Sessions has reportedly put the White House on notice: If Rod Rosenstein goes, I might go, too.

The Washington Post’s Sari Horwitz, Rosalind S. Helderman, Josh Dawsey, and Matt Zapotosky report that Sessions told White House counsel Don McGahn last weekend that if President Donald Trump fires Deputy Attorney General Rod Rosenstein — the man in charge of overseeing special counsel Robert Mueller’s Russia investigation — Sessions might have to quit.

Sessions’s warning apparently came after Trump grew furious at Rosenstein for approving the FBI raid on Trump’s longtime attorney and fixer Michael Cohen. In a rambling session with reporters last Monday, the day of the Cohen raid, Trump attacked Rosenstein, bashed the Russia investigation as a “witch hunt,” and mused about possibly firing Mueller.

The Cohen raid is separate and unrelated to the Russia probe, and involves hush money Cohen is said to have paid women, including porn actress Stormy Daniels, to buy their silence about affairs they had with Trump. But Rosenstein, as deputy attorney general, was still the one who had to sign off on the FBI raid on Cohen. That seems to have reignited Trump’s ire at Rosenstein.

But pressure on Rosenstein seems to have cooled in the intervening days, which might make Sessions’s resignation threat moot. “They’ve been saying I’m going to get rid of them for the last three months, four months, five months, and they’re still here,” Trump said Wednesday, at Mar-a-Lago, referring to Rosenstein and Mueller.

What to make of Sessions’s vow

It’s unclear just how serious Sessions is about possibly resigning if Trump fires Rosenstein. One source told the Washington Post that Sessions didn’t so much threaten to quit as try to “convey the untenable position that Rosenstein’s firing would put him in.”

But Sessions isn’t exactly at the top of the list of Trump’s favored Cabinet members. The attorney general angered Trump when he recused himself from the Russia investigation, leaving Rosenstein in charge.

“Sessions should have never recused himself, and if he was going to recuse himself, he should have told me before he took the job and I would have picked somebody else,” Trump told the New York Times last July.

But Sessions and Rosenstein departing together would certainly throw the Justice Department into chaos; the top three jobs at the DOJ would lack permanent, Senate-confirmed appointees. (Rachel Brand, the Associate Attorney General and No. 3 at the DOJ, announced she was leaving in February.)

Sessions’s attempt to be noble could backfire, accidentally solving one of Trump’s biggest conundrums: how to make the Russia investigation go away.

Rosenstein is in charge of the Russia investigation after Sessions’s recusal last year. That recusal makes Rod Rosenstein the acting attorney general on all matters Russia-related. But if Trump fires Rosenstein, the special counsel investigation falls to the next Senate-confirmed person in line, which, in this case, is Solicitor General Noel Francisco.

But if Sessions goes when Rosenstein goes, whoever becomes Sessions’s temporary replacement — the acting attorney general — would now oversee Mueller and the Russia probe. Under the Federal Vacancies Reform Act of 1998, Trump can fill that spot with any other Senate-confirmed person that he chooses — a loyalist, for example, like EPA Administrator Scott Pruitt. That acting attorney general could fire Mueller, shut down his investigation, or curtail his mandate.

Some lawmakers on Capitol Hill are pushing forward legislation that would protect Robert Mueller in the event Trump attempted to get rid of him. Those bills are unlikely to go anywhere for now — though Congress might wake up to a potential crisis if Sessions and Rosenstein depart as a team.