Sens. Thom Tillis, R-N.C., and Chris Coons, D-Del., introduced legislation Thursday that would protect special counsel Robert Mueller’s job, making it harder for him to be removed from the investigation into Russia’s interference in the 2016 election and possible ties to the Trump campaign.

What’s in the bill? Called the “Special Counsel Integrity Act,” the bipartisan legislation would allow a special counsel who gets fired to appeal the decision before a panel of federal judges. If the panel decides the removal was unwarranted, the special counsel would get reinstated.

Why it matters: Senators from both sides of the aisle have expressed concern about reports that President Donald Trump had considered removing Mueller. Under current regulations, if Deputy Attorney General Rod Rosenstein fired Mueller at Mr. Trump’s request, the special counsel would have no legal pathway to challenge the removal. Rosenstein has said he would not fire Mueller without good cause, but a top Justice Department official under Rosenstein could choose to carry out Trump’s order. The bill would retroactively take effect May 17, the day Rosenstein appointed Mueller special counsel.

A throwback to Watergate? Congress passed a law after the Watergate scandal that created the special prosecutor role, and gave the position significant independence from the executive branch. Under the law, a special prosecutor could not be removed by the Department of Justice at the president’s request. Congress allowed the law to lapse in the late 1990s, however, and it has not been reauthorized. Today, the special counsel role falls under federal regulations and has less independence. The Tillis-Coons bill would bring the investigation more in line with the post-Watergate system.

READ MORE: What we know — and what we don’t — about Mueller’s grand jury

Bipartisan warning to Trump: The bill sends a strong message to Trump from Republicans and Democrats alike: Don’t remove Mueller. Republican Sen. Lindsey Graham of South Carolina and Democratic Sen. Cory Booker of New Jersey are also working on a similar bill.

Tillis says: “It is critical that special counsels have the independence and resources they need to lead investigations.”

Coons says: “Our constitutional order depends on a system of checks and balances, grounded in the fundamental premise that no one is above the law. Ensuring that the special counsel cannot be removed improperly is critical to the integrity of his investigation.”

Will it pass? It’s too early to tell. The Senate and House would both need to pass a version of the legislation, and Trump would have to sign it into law. Even if this doesn’t reach the floor, it increases pressure on Trump not to interfere with Mueller’s investigation.