The news that President Trump last June nearly fired the special counsel Robert Mueller has revived interest in a pair of bills that would prohibit Mr. Trump from firing Mr. Mueller without good cause. The president’s recent attacks on the F.B.I., which seem intended to pave the way for Mr. Mueller’s ouster by putting his Russia inquiry under a cloud of suspicion, make the case for the bills even stronger.

But Republicans still resist. They want to contain the Russia investigation and worry that any concession to the Democrats will instead bolster its credibility. They have tried to mask these partisan motivations with constitutional objections to the bills. It is important to understand why those arguments are specious.

For context, one must go back to 1973, when Richard Nixon fired the special prosecutor Archibald Cox rather than turn over the Watergate tapes. The country was thrown into a political crisis, driven by uncertainty about how far Nixon would go to protect his presidency.

Congress eventually responded with the Ethics in Government Act of 1978. This law created what came to be known as the independent counsel, who was given the power to investigate the president and his aides if they were suspected of wrongdoing. The independent counsel was appointed by judges; not removable by the president; removable by the attorney general only for cause; and further insulated with an independent budget.