George Santos is far from the first member of Congress to be indicted while in office. Both chambers and both parties have endured their share of scandals. In 2005, for instance, F.B.I. agents discovered $90,000 hidden in the freezer of Representative William Jefferson, who was under investigation for bribery. He refused to step down, wound up losing his seat in the 2008 election, and was later sentenced to 13 years in prison. James Traficant was expelled from Congress in 2002 after being convicted of bribery and racketeering. Bob Ney resigned in 2006 because of his involvement in a federal bribery scandal.

But in one way, Mr. Santos is different from other members of Congress who have demonstrated moral failures, ethical failures, failures of judgment and blatant corruption and lawbreaking in office. What he did was to deceive the very voters who brought him to office in the first place, undermining the most basic level of trust between an electorate and a representative. These misdeeds erode the faith in the institution of Congress and the electoral system through which American democracy functions.

For that reason, House Republican leaders should have acted immediately to protect that system by allowing a vote to expel Mr. Santos and joining Democrats in removing him from office. Instead — not wanting to lose Mr. Santos’s crucial vote — Speaker Kevin McCarthy pushed a measure to refer the matter to the House Ethics Committee, notorious for its glacial pace, and the House voted predictably along party lines on Wednesday afternoon to follow that guidance.

If the House doesn’t reverse that vote under public pressure, it’s incumbent on the Ethics Committee to conduct a timely investigation and recommend expulsion to the full House, where a two-thirds vote will be required to send Mr. Santos back to Long Island.

Mr. Santos was arrested and arraigned in federal court last week on 13 criminal counts linked primarily to his 2022 House campaign. Mr. McCarthy and other members of the Republican leadership effectively shrugged, indicating that they would let the legal process “play itself out,” as the conference’s chair, Elise Stefanik, put it.

In addition to expulsion, the Republican leaders have several official disciplinary measures they could pursue, such as a formal reprimand or censure, but so far, they have done little more than express concern. Mr. McCarthy has several tough legislative fights looming, including negotiations over the federal budget to avoid a government default, and Mr. Santos’s removal might imperil the G.O.P.’s slim majority. In effect, Mr. Santos’s bad faith has made him indispensable.

His constituents believed he held certain qualifications and values, only to learn after Election Day that they had been deceived. Now they have no recourse until the next election.

The question, then, is whether House Republican leaders and other members are willing to risk their credibility for a con man, someone whose entire way of life — his origin story, résumé, livelihood — is based on a never-ending series of lies. Of course they should not be. They should have demonstrated to the American people that there is a minimum ethical standard for Congress and used the power of expulsion to enforce it. They should have explained to voters that their commitment to democracy and public trust goes beyond their party’s political goals.

At least some Republican lawmakers recognize what is at stake and are speaking out. Senator Mitt Romney of Utah reiterated his view that Mr. Santos should do the honorable thing and step aside, saying, “He should have resigned a long time ago. He is an embarrassment to our party. He is an embarrassment to the United States Congress.”

Similarly, Anthony D’Esposito and Mike Lawler, both representing districts in New York, are among several House Republicans advocating his resignation. Representative Tony Gonzales of Texas has gone a step further, calling for Mr. Santos’s expulsion and a special election to replace him. “The people of New York’s 3rd district deserve a voice in Congress,” he wrote on Twitter.

Mr. Gonzales gets at the heart of the matter. Mr. Santos has shown contempt for his constituents and for the electoral process. Mr. McCarthy and the other Republican House leaders owe Americans more.