A Democrat who lost to former Rep. Randy "Duke" Cunningham two years ago advanced easily to a runoff in a special election called after the congressman pleaded guilty to bribery charges.

On the Republican side, former Rep. Brian Bilbray appeared to have narrowly defeated political newcomer Eric Roach, according to unofficial results from Tuesday's balloting.

Democrat Francine Busby's campaign was viewed as an early test of her party's chances in the midterm elections. Busby said her campaign had attracted Republicans and independents, but it wasn't enough to avoid a runoff in California's 50th District, where Republicans outnumber Democrats 3-to-2.

"When we go on to June, people know that this district today voted for change in Washington," Busby told supporters. "We sent a message that we will no longer accept business as usual."

With 100 percent of the precincts reporting early Wednesday, Busby had 56,147 votes, or 44 percent, to lead all 18 candidates in the nonpartisan, all-on-the-ballot format.

Bilbray, a lobbyist, had 19,366 votes, or 15 percent, while Roach, who spent $1.8 million on his own campaign, had 18,486 votes, or 14 percent.

Late Tuesday, when 99 percent of the precincts had reported, Roach spokesman Stan Devereux said the election was too close to call on the Republican side.

"It may be another day or two until we know what the outcome is," he said.

Bilbray, however, seemed confident of victory, saying his campaign against Busby would begin on Wednesday.

The top finisher from each party competes in a June 6 contest for the eight months remaining on Cunningham's term — and then immediately begins campaigning for the November election.

Cunningham had represented the district from 1993 until he resigned in disgrace late last year. In March, he was sentenced to more than eight years in federal prison on charges of evading taxes and accepting $2.4 million in bribes from defense contractors.

"Career politicians are the ones ruining everything," said Juanita Velasco, a 55-year-old Democrat from Del Mar who voted for Roach. "They just keep writing the checks and we keep footing the bills."

John Towers, a 51-year-old Republican who also voted for Roach, said he felt betrayed not only by Cunningham, but by the policies of the Bush administration. "I wouldn't be surprised if a lot of Republicans are so disgusted they just stay home," said the college math instructor from Cardiff.

The campaign had turned sharply negative in the week before the election.

Bilbray, a surfer and one-time lifeguard, was attacked in a mailer from the California Republican Assembly, a grass-roots conservative group, that called him "a Democrat posing as a Republican." The Bilbray campaign attacked Roach as a mystery man trying to buy an election.

Former state Assemblyman Howard Kaloogian failed to regain his footing after bloggers discovered an embarrassing photo mix-up on his campaign Web site. Photos purportedly taken during Kaloogian's visit to Iraq of a tranquil Baghdad street scene had been taken in Istanbul, Turkey.