President Donald Trump is toying with firing special counsel Robert Mueller, openly attacking him on Wednesday morning by calling him biased. Now a bipartisan group of senators is trying to save Mueller’s job.

Lawmakers led by Republicans Lindsey Graham (R-SC) and Thom Tillis (R-NC) and Democrats Cory Booker (D-NJ) and Chris Coons (D-DE) introduced a long-shot bill Wednesday that would give judges a chance to reinstate Mueller if Trump fires him without a good reason.

“In order to avert a constitutional crisis, Congress has to act to protect Mueller’s investigation,” Rep. Terri Sewell (D-AL) told me in an email.

Tough rhetoric aside, the bill has little chance of making it through the House and Senate with margins big enough to overcome a certain presidential veto. There are also legitimate questions about whether it would be constitutional because the legislative branch isn’t supposed to meddle in the everyday functioning of the executive branch

Still, the simple fact that Republicans are abruptly working to pass the bill illustrates the mounting concerns about Mueller’s job security in the wake Trump’s outbursts after the FBI raided his lawyer Michael Cohen’s office Monday.

“A nation of laws cannot exist if the people tasked with enforcing them are subjected to political interference or intimidation from the president,” Booker said in an emailed statement.

The problem for Booker and his allies is that they have little to no realistic chance of preventing Trump from axing Mueller.

How the Senate would protect Mueller

The new bill, called the Special Counsel Independence and Integrity Act, would give Mueller a chance to appeal to a special three-judge panel if Trump fires him.

Current law says that Trump can only fire Mueller “for good cause,” meaning if Mueller does something wrong like major misconduct. The new bill would give Mueller 10 days to challenge his termination in a specially convened court. A three-judge panel would then decide if Trump had a valid reason to fire Mueller, and they could reinstate him if Trump didn’t.

The bill would also require that the Justice Department save all the documents generated by the special counsel’s office while the judges review Mueller’s firing.

The legislation is a hybrid of two bipartisan bills introduced in August, one by Graham and Booker, and another by Coons and Tillis.

Those bills floundered for months as Graham and Tillis wavered in their support. It’s only when Trump’s new direct attacks against Mueller started on Monday, after the FBI raided Cohen’s office, that the senators hammered out a deal on a combined bill.

One of the reasons the earlier two Senate bills didn’t advance was lingering concern among some Republicans that changing the rules on firing Mueller might be unconstitutional.

The idea is that Mueller is working in the executive branch as part of the Justice Department, and Congress isn’t supposed to interfere in the functioning of another branch of government.

Sens. John Kennedy (R-LA) and Jeff Flake (R-AZ) both told Vox’s Tara Golshan last month that they thought taking action might violate the Constitution.

Legal scholars who talked to Golshan said that a 1988 Supreme Court case, Morrison v. Olson, probably means that the law would be okay. Congress is typically allowed to shape the other branches of government; it just can’t directly interfere.

But getting to the point of a potential legal challenge is highly unlikely.

The bill is probably symbolic, as Senate Majority Leader Mitch McConnell doesn’t appear interested in allowing a vote on a bill to protect Mueller.

“I haven’t seen a clear indication yet that we need to pass something to keep him from being removed,” McConnell said Tuesday.

The bill is unlikely to pass

The legislation would first have to go through the Senate Judiciary Committee. That committee’s chair, Sen. Chuck Grassley (R-IA), is pushing for the committee to review the bill on Wednesday.

But even if the Judiciary Committee approves it, and McConnell changes his mind and allows a vote, the bill would also have to pass the House, where the odds of a vote on it appear low.

“Given the current leadership in the House and their recent history of turning a blind eye to, or even enabling, this president’s actions, I find it highly unlikely that they would act to protect” the special counsel, Rep. Jim Himes (D-CT) told me in an email.

House Democrats are trying to protect Mueller, and they’ve drafted several bills of their own. Those bills haven’t gone anywhere yet, although Democrats continue to push.

Even if the bill doesn’t have a shot at becoming law, the sudden resurrection of bipartisan support in the Senate shows just how scared lawmakers are that Trump’s recent attacks might be a prelude to firing Mueller. If Trump does so anyway, the question will be what, if anything, Republicans do.