The state senator who succeeded Rep. Hilda Solis (D-Calif.) in Sacramento is considered to be the leading contender to replace her in Congress, local political observers say.

Sen. Gloria Romero’s (D) district encompasses Solis’s district and she has told local newspapers that she is very interested in running. But she is still only one name in a crowded field of potential candidates.

The race could be fought along ethnic or labor-business lines, said Los Angeles pollster Andre Pineda, who did Hispanic polling for the Obama presidential campaign.

Romero, Chu, or Cedillo would likely be popular with labor, he said, while one of the Calderons would draw more business support. The question, Pineda said, is whether local labor leaders – heads of the Service Employees International Union and the Los Angeles County Federation of Labor – will try to clear the field to avoid splitting the labor vote in a crowded primary and handing the race to one of the Calderons.

“Labor is going to care very much about this seat,” Pineda said, adding that unions have been asserting more influence in recent elections in the area.

Pineda also sees a potential ethnic dynamic. The population of the district is 62 percent Hispanic, and 18 percent Asian. It has one of the lowest percentages of non-white Hispanics in southern California.

That would seem to put Chu at a disadvantage compared to the Hispanic candidates. But Pineda said the population dominance does not carry over to turnout. Hispanics, he said, routinely account for less than half of the votes. That means that a candidate who unites Asian votes and wins white votes could win along ethnic lines, especially if Hispanics are split.

Split votes are a real possibility in the open primary that could decide the race. Candidates of all parties run together, and if a candidate gets more than 50 percent of the vote, he or she wins outright and there’s no general election.

Once Solis vacates her seat, California Gov. Arnold Schwarzenegger will have 14 days to call a special election to occur within 112 to 126 days (16 to 18 weeks). The open primary takes place eight weeks before the general.

Some observers are already looking at the March 3 election for Los Angeles mayor as a date for the primary. But it appears state law would not allow for it to be held so quickly by mandating that the primary must be held at least eight weeks after the vacancy. Presumably, Solis would not quit Congress until she is confirmed. That can’t happen until Obama is sworn in.

Democrats are likely to keep the seat in Los Angeles’s ethnic, working class eastern suburbs. Republicans did not put a candidate against Solis in this year’s general election, and in 2004 John Kerry won the district, which includes much of East Los Angeles and the San Gabriel Valley, with 62 percent of the vote.

The candidates come with various strengths and weaknesses. Romero’s Senate district encompasses Solis’s congressional district. Chu was elected to the equalization board from a district that includes most of Los Angeles County, with 8.5 million residents. Since it handles taxes, the board is considered a strong position from which to raise money. Cedillo represents an adjacent Senate district, but members don’t have to live in the district they seek to represent.

The Sacramento Bee reported last week that, as reporters gathered around Cedillo at the Capitol to ask about his interest, Romero walked up, said “I can beat them all,” and walked off.