It has been a tough week for Republicans as they prepare to take control of both houses of Congress beginning next week.
Representative Michael Grimm of New York announced his resignation late Monday, just days after pleading guilty to felony tax evasion.
Grimm had already stirred controversy in January after being recorded on camera threatening to throw a reporter off a balcony and break him "in half, like a boy."
In his resignation statement, the former Marine and FBI agent said he does not believe he "can continue to be 100 percent effective in the next Congress" and is stepping down on January 5 "out of respect for the office and the people" he represents.
Grimm reportedly talked with House of Representatives Speaker John Boehner before deciding to step down. Immediately after his guilty plea on December 23, the disgraced congressman had told reporters he would not resign.
In more bad publicity for the party, the number three Republican in the House of Representatives, Steve Scalise of Louisiana, is now under scrutiny for addressing a gathering of white supremacists years ago.
An aide for Scalise issued a statement confirming the congressman appeared in 2002 before the European-American Unity and Rights Organization, founded by former Ku Klux Klan leader David Duke. But the aide said Scalise, then a state lawmaker, was only building support for his policies and "has never been affiliated with the abhorrent group in question."
The revelation could harm Republican efforts to reach out to minorities, who overwhelmingly support Democrats in each U.S. election.
Grimm won re-election in November despite the fact that he was under indictment. He was charged in April on 20 counts related to a health food restaurant he co-owned before being elected to Congress in 2010. He was accused of underreporting around $1 million in wages and sales, in part by hiring illegal immigrants and paying them in cash.
New York Governor Andrew Cuomo is expected to schedule a special election to fill Grimm's seat, and attention has already turned to possible contenders.
Grimm, meanwhile, is set to be sentenced on June 8 and could face up to three years in prison.
Some information for this report came from AP and Reuters.
