Mere hours after Democrats retook the House, President Donald Trump announced the resignation of Attorney General Jeff Sessions and the appointment of Matthew Whitaker as the acting attorney general. Whitaker, formerly the Department of Justice’s chief of staff, has expressed skepticism about special prosecutor Robert Mueller’s probe, leading to renewed concerns that Mueller's job is in jeopardy.

Given the available information, these concerns seem justified. But there is a solution: The Senate urgently needs to pass a bipartisan bill that cleared the Senate Judiciary Committee in April. The bill, The Special Counsel and Integrity Act, would protect Mueller and his vital investigation from executive meddling.

Republican opponents of the bill suggest it might be unconstitutional. That is mistaken. The bill is part of an important constitutional and legislative tradition that works to constrain the power of presidents and prevents them from firing executive employees at will.

The bill is part of an important constitutional and legislative tradition that works to constrain the power of presidents and prevents them from firing executive employees at will.

Despite the statements of Republicans like Senate Majority Leader Mitch McConnell, Mueller does need congressional protection due to a flaw in our constitutional system. This flaw could permit the new attorney general to fire a special counsel for political reasons, including to shield the president from investigation.

That same defect has caused problems in the past, sparking a constitutional crisis during Watergate when President Richard Nixon sought to have special prosecutor Archibald Cox fired. Cox was investigating Nixon’s involvement in the Watergate break-in and the subsequent cover-up. Nixon first asked Attorney General Elliot Richardson to fire Cox. When Richardson resigned rather than carry out the order, Nixon asked Deputy Attorney General William Ruckelshaus, who also resigned. Finally, Nixon appointed Robert Bork, who complied in firing Cox.

There are now internal justice department regulations that protect Mueller from Cox’s fate. But they could be revoked, and they are even weaker than at Cox’s time. We cannot count on the courts to save Mueller under the current system.

After Nixon’s resignation, Congress realized that it could not trust presidents to protect those charged with investigating them—or to honor Justice Department rules if those rules risked getting them into hot water. So, Congress passed a law creating an “independent counsel” that insulated criminal investigations of a president from political considerations and illegitimate executive branch interference. The statute made clear that courts can stop a president from firing an independent counsel without good cause.

However, that important legislation expired after Bill Clinton argued it had enabled Kenneth Starr to launch what many believed was an overly broad investigation that veered into Clinton’s sex life. Even while it was in force, the law had an opponent in Justice Antonin Scalia, whose 1988 dissent in Morrison v. Olson argued that the law wrongly restricted a president’s power. In Scalia’s view, prosecutors were carrying out purely executive functions. He argued it would violate the president’s power as head of the executive branch to restrict his hiring and firing ability over the independent counsel.

The Republican opposition to the current bill to protect Mueller relies on a similar argument. Sen. Orrin Hatch, for example, has argued that the proposed bill is unconstitutional because prosecution is a “core executive function,” directly echoing Scalia.

But Hatch and other Senate Republicans who claim the bill is potentially unconstitutional should not use Scalia as their guide. In Morrison, Scalia was a sole dissenter. The rest of the Supreme Court voted to uphold the independent prosecutor law. This added to a long tradition of recognizing the constitutionality of laws that sought to protect core government functions from presidential abuse.

The most famous law in this tradition was passed after a presidential assassination. In 1881, a disgruntled campaign worker, Charles Guiteau, shot and killed President James A. Garfield. Guiteau felt that his work on the campaign entitled him to a patronage job in the federal government. Such a stark example of the politicization of the federal bureaucracy led to the passage in 1883 of the Pendleton Civil Service Reform Act. The law insulated civil servants from political firings and made courts responsible for protecting them. This assertion of political independence for government workers made it possible for them to carry out their legislatively-assigned tasks without fear of reprisal by a president. The law emphasized that the role of executive officials was to carry out the law, not manipulate it to advance their own agendas.

A 1935 court case, Humphrey’s Executor, upheld Congress’s right to protect even high-level officials from firing. President Franklin Roosevelt sought to fire a commissioner of the Federal Trade Commission because he didn’t share Roosevelt’s progressive politics. But the Supreme Court ruled that the president’s power of removal was not “illiminable” or without restriction. The president’s power to fire even high ranking officials is limited when those officials occupy a quasi-legislative or quasi-judicial role.

Today’s bill to protect Mueller fits squarely in the tradition of both the post-Nixon independent counsel law and the long history of laws and cases protecting executive officials from political retaliation by the president.

Today’s bill to protect Mueller fits squarely in the tradition of both the post-Nixon independent counsel law and the long history of laws and cases protecting executive officials from political retaliation by the president. The abiding principle has been that civil servants must be protected, unless they fail in their job duties, especially when they are in roles that might challenge a president’s personal interests.

That is clearly relevant to Mueller. His investigation is probing Trump’s and his campaign’s possible links with the Russian government — and possible obstruction of justice. Mueller’s job is to make sure that the highest government official in the land does not flout the basic restraints that all government officials and citizens must abide by. He can’t do that job effectively if he can be removed at will by the president.

Fears about the bill restricting the president’s rightful power and giving too much leeway to prosecutors are overblown. The Mueller bill is less expansive than the independent counsel law passed after Watergate, and even conservative legal scholars sympathetic to Scalia believe it to be constitutional. It calls for the special counsel to remain within the Justice Department, still supervised by the attorney general. Robust protections for prosecutors could make them overly eager, but that risk pales in comparison to the specter of a president who can manipulate the justice system to hide his own wrongdoing. As James Madison said, “No man is allowed to be a judge in his own cause.”

Though a more long-term fix that insulates presidential investigators outside the Justice Department would be optimal in terms of protecting prosecutorial independence, the current bill will suffice in what is quickly becoming an emergency situation.

Even in a democracy, no official can simply be trusted to do the right thing. Our country needs checks that ensure public officials work in the public interest. The law must be strong enough so that someone like Trump cannot bully his way out of accountability.

Passing this bill to safeguard Mueller’s investigation is constitutionally sound and necessary for maintaining the integrity of our democracy. Arguments from an unauthoritative Scalia dissent must not stop the Senate from fulfilling its constitutional obligation to check the self-interested motives of the president.