The re-election of Rep. William Jefferson (D-La.) poses a major dilemma for House Democratic leaders as they try to make good on their promise to make the next Congress the "most honest, most open and most ethical Congress in history," say groups calling for ethics reform.

"Nancy Pelosi has said that this is going to be the cleanest Congress ever, and Jefferson has got to be the dirtiest congressman out there," says Melanie Sloan, executive director of the Citizens for Responsibility and Ethics in Washington, D.C. "It's a big dilemma for them."

Jefferson won re-election in a runoff on Saturday, despite being at the center of a federal bribery investigation. He has not been indicted and has strongly denied allegations of wrongdoing. 

In court papers, FBI agents say Jefferson was videotaped accepting marked money supposedly to pay a bribe to a Nigerian official.  The FBI says $90,000 in marked money was found in Jefferson's freezer during a raid.

"Obviously you have to weigh very carefully the wishes of the constituents who have chosen to re-elect this guy," says Meredith McGehee, policy director at the Campaign Legal Center. "At the same time, you have two figures who've pleaded guilty to bribing him."

Brendan Daly, spokesman for Pelosi, brushed aside the suggestion that the Jefferson case presented any sort of quandary for Democrats. "We have taken action," said Daly, pointing to the Democrats' move in June to vote Jefferson off the Ways and Means Committee after court documents first made public allegations that Jefferson had been caught on tape.

Congressional aides say that while it is unlikely that Jefferson would regain his post on the Ways and Mean Committee, other assignments could be made when the House steering committee meets later in the week.

Further complicating the Democrats' dilemma is the question of whether Jefferson should be treated differently than Rep. Alan Mollohan of West Virginia, another Democratic congressman facing an FBI probe.

The FBI is investigating whether Mollohan financially benefited from steering millions in federal funds to non-profit groups connected to him.  Mollohan has kept his seat on the House Appropriations Committee and is now in line to become the chairman of the subcommittee overseeing the Justice Department budget.  Mollohan has denied the allegations and has not been charged with a crime.

"What is the standard?" asks Sloan. "Are you going to lose your committee assignment because you're under investigation or only when you're on tape soliciting a bribe?"

Reform advocates would also like to see Democrats support a complete overhaul of the "peer-reviewed" system for investigating members. "The current ethics process is a total sham," says McGehee.