Rep. Gary Condit, now better known as the congressman whose young mistress disappeared after their extramarital affair, has decided to seek re-election in 2002.

The once-unbeatable Democrat filed less than an hour before the deadline on Friday.

"I'm running," Condit told the crowd of supporters, reporters and photographers as he walked into the Stanislaus County Courthouse to complete the necessary paperwork. "It was a very difficult decision for me."

Condit, who was first elected in 1989 and has easily won re-election six times, had been quiet about his plans.

Several Democrats are set to run in the March primary, including state Assemblyman Dennis Cardoza, a one-time Condit aide and political protege.

"I expected him to try and run for re-election," Cardoza said. "He probably sees this as one way he can redeem himself some way."

Condit is also facing a redrawn district this year. California's population increase under the 2000 census gave the state its 53rd House seat, requiring redistricting by the Democrat-controlled state assembly. Forty percent of voters will be new to the district.

Condit's hold on the congressional seat was shaken following Chandra Levy's disappearance in May. The 24-year-old intern for the Bureau of Prisons in Washington is from Condit's district, and questions mounted about her connection to the married congressman.

Condit, 53, eventually admitted that he had been romantically involved with Levy, according to a police source.

He kept silent publicly for more than three months, finally giving a series of poorly received print and broadcast interviews in which he acknowledged "very close" relations with Levy but denied any involvement in her disappearance.

Police have said they do not consider Condit a suspect, although they interviewed him four times and searched his Washington condominium looking for clues.

Condit on Friday deflected any questions about Levy, saying the media would have to decide if he could run a campaign that did not focus on her case.

"You guys will have to decide if you're going to be fair to me or not and whether that's your main issue," Condit told reporters. "I'm going to dwell on my record and what I've done for the valley and what I'm going to do for the future."

Condit submitted 1,500 voter signatures with his campaign papers to go with the 1,939 valid signatures he turned in earlier. A candidate must have 3,000 valid signatures to qualify for the ballot or pay a filing fee.

Levy's mother, Susan, said she had no comment on Condit's decision to run again.

Once among the most popular Democrats in the House, Condit has been ostracized by his own party. Prominent Democrats, including California Democratic Party Chairman Art Torres, are backing Cardoza.

Leading Democrats including House Minority Leader Dick Gephardt and California Gov. Gray Davis, a longtime Condit friend and political ally, have criticized the congressman for not being more forthcoming.

Even Condit's son had said publicly he hoped his father would not seek re-election to spare him more criticism. But he reversed himself Friday, and abandoned his own bid for the state Senate to campaign with his father.

"He should run," said Chad Condit, who accompanied his father at the courthouse. "He's right to run."

Democrats are worried about losing Condit's seat, which could undermine their chances of winning a majority in the House next year. Republicans now have a 10-seat advantage, 221-211, with two independents and one vacancy.

"Hold on to your hat," said state Sen. Dick Monteith, an erstwhile Condit ally who is seeking the Republican nomination for the seat.

The Associated Press contributed to this report.