House Democrats have put forward a resolution on expelling from office a New York congressman, George Santos, forcing Republicans to take a stand on a colleague exposed as a serial fabulist and under federal indictment.

Representative Robert Garcia, a California Democrat, brought the privileged resolution to the House floor on Tuesday, forcing the Republican-controlled body to dispense with the measure within two days.

The one-sentence resolution requires a two-thirds majority to pass and is expected to fail, but will increase pressure on Republicans who have stood by Mr. Santos so far. The GOP holds a narrow majority in the House and has mostly defended the congressman’s right to continue representing New York’s 3rd congressional district covering Nassau County and parts of Queens.

Republicans could also muster a majority vote to table the resolution or refer it to the House Ethics Committee. Speaker McCarthy has said he prefers the case be handled by the committee, which announced in March that it had launched a probe into alleged illegal activity during Mr. Santos’s campaign. Mr. McCarthy has also said he would not support Mr. Santos’s re-election.

Putting forward the resolution, Mr. Garcia said, “George Santos is a fraud and a liar, and he needs to be expelled by the House … Republicans now have a chance to demonstrate to Americans that an admitted criminal should not serve in the House of Representatives.”

Mr. Garcia has the backing of Democratic party leadership, including the House minority leader, Hakeem Jeffries, of New York.

“George Santos is a serial fraudster. He blatantly lied to voters in New York’s 3rd congressional district and won an election under false pretenses,” Mr. Jeffries said. “It’s time for him to be held accountable under the Constitution.”

The bill has 48 co-sponsors, all of whom are Democrats, including New York’s Ritchie Torres, Daniel Goldman, Adriano Espaillat, Jamaal Bowman, Nydia Velazquez, and Patrick Ryan. Mr. Garcia first introduced the resolution in February.

House Democrats grappled with their approach to the vote during a closed-door meeting early Wednesday, with some urging party members to oppose sending the resolution to the Ethics Committee, and others saying that forcing a vote would be counter-productive, Politico reported.

More than 10 House Republicans have called on Mr. Santos to resign, including some from New York, but the party’s leadership has said he should have his day in court. Mr. Garcia’s resolution will compel Republican representatives of New York to publicly side with Mr. Santos, or break with the party’s leaders.

Republicans hold a tenuous majority in the House, and Mr. Santos’s district could flip to Democratic control if he loses his position. He has already said he plans to run for re-election, though the Nassau County GOP has called for his resignation.

Mr. Santos did not respond to a request for comment. He told CBS News that House Democrats are “trying to play judge and jury and trying to hold people guilty before they’ve even been given a free shot at a trial.”

The House has expelled only five lawmakers in its history, most recently in 2002, when Democrat James Traficant was booted after being convicted on felony charges.

Last week, Mr. Santos was arrested on federal criminal charges for alleged fraud, money laundering, theft of public funds, and false statements. He pleaded not guilty to the 13-count indictment, was released on a $500,000 bond, and decried the charges as a “witch hunt.”

“I will fight to defend myself,” he said.

After taking office, reports exposed a litany of lies Mr. Santos had told voters about his background, including fabrications about his professional history, education, and his Jewish background. He also falsely claimed to have been a star volleyball player in college, to have run an animal charity, and that his mother died in the 9/11 terror attacks.

Investigations also uncovered criminal charges in Brazil from 2008 and 2011 related to embezzlement and a stolen checkbook. Mr. Santos announced his re-election campaign last month, saying, “This is about TAKING BACK our country and restoring greatness back to New York.”