Former Rep. Brian Bilbray (R-Calif.) has 198,809 reasons to make a political comeback, if he chooses to.

That’s the eye-popping amount of cash sitting in his old Congressional campaign account — a tidy starting point for any of the dozen or so Republicans who are reported to be considering entering the race to replace retiring Rep. Duke Cunningham (R-Calif.).

Bilbray’s disposition is one of the early mysteries of this nascent contest — and he didn’t respond to a phone message left at his office Wednesday afternoon.

But there are many other intriguing questions yet to be answered, on both the Republican and Democratic sides. The most fundamental in each case: How many candidates will actually run?

“You’re going to see a very crowded field, at least at the outset,” predicted John Nienstedt, president of Competitive Research and Communications, a San Diego-based independent polling and consulting firm. “They may not all make it to the ballot.”

Three candidates have already entered the Republican primary: Former state Assemblyman Howard Kaloogian, state Sen. Bill Morrow and businessman George Schwartzman, but several others could follow.

Kaloogian and Morrow are rock-ribbed conservatives who are considered serious contenders. Both have run unsuccessfully for higher office — Kaloogian sought the Republican Senate nomination in 2004 and Morrow was the runner-up to now-Rep. Darrell Issa (R-Calif.) in the 2000 primary for the adjoining 49th district seat. What’s more, Kaloogian has been associated with several conservative grass-roots groups that have valuable donor lists.

“I don’t think there’s any question that the base candidate is Kaloogian,” said Sal Russo, a Sacramento-based Republican consultant who is working for Kaloogian.

But Morrow said his 13 years of legislative experience will be a selling point in the primary — all the more so because San Diego-area voters are reeling from the scandals that prompted Cunningham to retire and a series of explosive ethics cases involving local politicians.

“We need to restore confidence in our elected government officials,” Morrow said.

The third candidate formally in the race, Schwartzman, is considered a long shot. His political claim to fame is finishing ninth in the field of 135 candidates who ran for governor in the 2003 special election. (Observers suggest that Schwartzman did so well because some voters confused him and the ultimate victor, Arnold Schwarzenegger.)

Besides Bilbray, who held a southern San Diego County seat until 2000 and who recently moved to Cunningham’s district, the field of other possible GOP candidates includes: Businessman Steve Francis, if he loses his bid to become San Diego mayor; ex-San Diego Mayor Susan Golding; physician Robert Hertzka; San Diego County Supervisor Bill Horn; San Diego City Councilman Brian Maienschein; San Diego County Treasurer and Tax Collector Dan McAllister; Escondido Mayor Lori Holt Pfeiler; state Assemblyman George Plescia; San Diego County Supervisor Pam Slater-Price; state Assemblyman Mark Wyland and California Division of Consumer Affairs Director Charlene Zettel.

It’s a dizzying field of seasoned pols and promising novices, with an array of ideologies, life experiences and political strengths.

“I would bet on a conservative nine times out of 10, but a moderate could win because we’re looking at so many candidates,” said Kevin Spillane, a GOP consultant in Sacramento. “We may not just be looking at an ideology primary, but a personality, popularity contest.”

Of the group of potential candidates, Slater-Price appears to be the closest to joining the race.

“We believe that she’s a perfect fit for the district,” said John Weil, her chief of staff.

Because she is a woman, and a moderate, Slater-Price is poised to benefit from any split among conservative candidates.

“As a county supervisor, you fly below the radar screen, but she’s pretty popular,” Nienstedt said.

She also appears to be a solid fundraiser: Weil said Slater-Price has raised close to $500,000 for her races, even though contribution limits are $500 and candidates for county offices are prevented from accepting corporate and political action committee money.

But it’s far too early to say if Slater-Price would be the lone moderate in the field, since Bilbray and several others also fit that bill.

“Some of these [Republican] constituencies will really be divided,” said Arnold Steinberg, a Republican pollster and consultant in Southern California.

Political observers would also watch Plescia and Wyland if they were to enter the primary.

“George Plescia, if he announces is probably going to be a frontrunner, because of the overlap” between his legislative district and the Congressional boundaries, said Doug Farry, a former Capitol Hill aide who now runs TechNet, a trade association for high tech companies.

But Plescia, who is seen as a stellar fundraiser, may not run because he has a clear shot at Morrow’s Senate seat in 2006, when Morrow is term-limited.

Wyland, meanwhile, is a potentially potent candidate because he is a stalwart of anti-immigration forces in Sacramento and has earned praise from Rep. Tom Tancredo (R-Colo.), a national leader on the issue, which could play well among certain segments in this district near the U.S.-Mexico border. But Wyland is a former aide to Morrow and is likely to defer to his old boss if Morrow runs for Congress.

Meanwhile, on the Democratic front, Francine Busby, a college lecturer who took 37 percent of the vote as the nominee against Cunningham last year, is the only candidate in the field, and national Democrats appear happy with her. Busby saw her once-sluggish fundraising surge as Cunningham’s problems mounted in recent weeks, and her campaign believes an open seat contest expands her financial potential.

“I’m not going to lie to you — we would have loved to have run against a scandal-plagued incumbent,” said Busby spokesman Brennan Bilberry. “On the other hand, people are so open seat-centric.”

Bilbray added that Busby has been getting more media attention than the would-be Republican contenders, since Cunningham announced last week that he would not run again.

T.J. Zane, a San Diego-based Republican consultant, said that Busby is not to be taken lightly, and will benefit from the fact that this is her second campaign.

“She ran the most credible campaign in recent history against Cunningham,” he said.

But Republicans seem confident about their prospects — regardless of their nominee — in a district that gave President Bush 55 percent of the vote last year.

“It’s a Republican seat,” said Carl Forti, communications director of the National Republican Congressional Committee. “We look forward to welcoming whoever wins the primary to Washington next December.”