Washington ? House Democrats, determined to make an election-year point about ethics, voted 99-58 Thursday night to strip Rep. William Jefferson of his committee assignment while a federal bribery investigation runs its course.

The rank and file acted despite a last-minute plea by the embattled Louisiana lawmaker and persistent complaints from the Congressional Black Caucus that there was neither rule nor precedent for the action.

Jefferson has not been indicted and maintains his innocence. In remarks to reporters, he conceded that “serious allegations” swirl around him.

After weeks of defiance, he also left open the possibility that he might at last surrender the seat voluntarily before the issue reaches the House floor for final action. “I don’t want to speculate,” he said.

Within an hour of the vote, Jefferson disclosed he had offered Wednesday to step aside on the condition that the caucus establish a rule covering cases like his and that his seat on the powerful Ways and Means Committee go temporarily to a fellow Louisiana Democrat, Rep. Charles Melancon.

“Ms. Pelosi politely declined my offer,” he said in a written statement, referring to Rep. Nancy Pelosi, of California, the Democratic leader. Pelosi’s office confirmed the exchange.

The three-hour closed-door meeting marked the culmination of a drive by Pelosi to take action. “This isn’t about proof in a court of law. This is about an ethical standard,” she told reporters.

“I wish the White House would follow our lead on this,” she added. Democrats have vowed to make ethics a cornerstone of the campaign for control of the House and have accused Republicans of presiding over a “culture of corruption.”