Senators from both parties on Nov. 16 called for an ethics probe into Sen. Al Franken (D-Minn.) after broadcaster Leeann Tweeden said he "forcibly kissed" and groped her in 2006. (Bastien Inzaurralde,Alice Li,Rhonda Colvin/The Washington Post)

Sen. Al Franken (D-Minn.) faced swift condemnation and bipartisan calls for an ethics investigation on Thursday after a Los Angeles radio broadcaster accused him of forcibly kissing and groping her in 2006.

Franken first issued a brief apology, saying his actions were intended to be funny and that he didn’t recall the incident the way Leeann Tweeden did. He later issued a longer apology: “There’s no excuse,” he said in a subsequent statement, adding that he would “gladly cooperate” with an ethics investigation.

That looks likely to happen. At least half a dozen Senate Democrats urged their chamber’s six-member, bipartisan ethics committee to investigate the allegations. Franken could face censureship or even expulsion from the Senate.

“Sexual harassment is never acceptable and must not be tolerated,” Senate Minority Leader Charles E. Schumer (N.Y.) said in a statement.

The Senate has wide latitude to kick out members, said Cornell Law Professor Josh Chafetz, though it hasn’t happened since the Civil War. Kicking out a senator would require a two-thirds vote by the full Senate — so all 52 Republicans and 15 Democrats.

Other top Democrats, including Franken’s colleague from Minnesota, Sen. Amy Klobuchar, and Sen. Patty Murray of Washington — the highest-ranking female Senate Democrat — urged their colleagues to investigate Franken.

“This should not have happened to Leeann Tweeden,” Klobuchar said in a statement. Sen. Elizabeth Warren (D-Mass.), who has teamed up with Franken on messaging videos, said his behavior was “unacceptable and deeply disappointing.”

And Sen. Kirsten Gillibrand (D-N.Y.), who a day earlier called sexual harassment a “serious” problem in Congress, said of the allegations against Franken: “This kind of behavior is unacceptable and should not be tolerated anywhere in our society.”

Sen. Kirsten Gillibrand (D-N.Y.) said Nov.15 that "there is a serious sexual harassment problem in Congress." Gillibrand is among several lawmakers introducing a bill to revise procedures for reporting harassment in Congress. (Reuters)

Tweeden’s account of harassment came two days after a House hearing where lawmakers acknowledged that sexual harassment is a pervasive problem on Capitol Hill and proposed legislation to make it easier for victims to report sexual misconduct by lawmakers.

Franken was critical of Hollywood mogul and Democratic megadonor Harvey Weinstein after numerous actresses accused him of sexual assault. At the time, Franken said that the accused harassers’ lackluster responses to their accusers leads to a culture of sexual misconduct, and he gave campaign contributions he had received from Weinstein to the Minnesota Indian Women’s Resource Center.

Franken is a prolific fundraiser for the Democratic Party and has emerged as one of their most effective messengers on health care and taxes. Earlier this week he was sending out a fundraising email through the Democratic’s Senate campaign arm joking that he’d get “Women’s Senate Network” tattoo to help elect female senators.

Broadcaster Leeann Tweeden said Sen. Al Franken (D-Minn.) "forcibly kissed" and groped her in 2006. Here's what Franken has said in the past about sexual violence. (Bastien Inzaurralde/The Washington Post)

Senate Republicans’ campaign arm immediately tried to make Franken a liability for Democrats, blasting out emails to reporters demanding that vulnerable Democrats up for reelection next year give back money Franken raised for them. Franken won reelection to a second term in 2014 with 53 percent of the vote. He’s up for reelection again in 2020.

Senate Majority Leader Mitch McConnell (R-Ky.), who is dealing with political fallout from allegations of sexual misconduct against GOP Senate candidate Roy Moore, also immediately called on the ethics committee to investigate Franken. McConnell has not ruled out similar investigations into Moore if the defiant conservative wins his special election in Alabama next month.

Minnesota’s Democratic-Farmer-Labor Party said it stood with Franken’s accuser: “We are incredibly disappointed in Senator Franken,” said party chairman Ken Martin in a statement.

Over the past week, many Democrats have been critical of Senate Republicans for originally hesitating to call for Moore’s ouster. But very few Democrats gave Franken a similar benefit of the doubt, especially given that his accuser shared photographic evidence. In the photo, Franken is posing with his hands over or on Tweeden’s chest as she slept when they were returning from a 2006 USO tour.

Franken would win a hard-fought election to the U.S. Senate two years later.

David Weigel, Ed O’Keefe, Paul Kane, Josh DuLac, Amy Wang and Karoun Demirjian all contributed to this report.