Voters head to the polls in California’s 48th district today in a special open primary to choose a successor to former Rep. Christopher Cox (R-Calif.), the new chairman of the Securities and Exchange Commission.

The 17-candidate field has two frontrunners, state Sen. John Campbell (R) and former state Assemblywoman Marilyn Brewer (R).

Campbell is the favorite of the GOP establishment, and that might be enough to win in a staunchly Republican Orange County district. Brewer is trying to appeal to moderate Republicans, independents and Democrats (voters can choose any candidate, regardless of party, in today’s election).

But the race also has one wild card: James Gilchrist, co-founder of the controversial Minuteman Project, which has stationed sentries along the U.S.-Mexico border to prevent illegal immigration. Gilchrist, who is running as a member of the American Independence Party, could marshal significant support from conservative voters — perhaps even enough to deny Campbell the 50 percent of the vote he would need to avoid a runoff or make Brewer the GOP nominee.

If a candidate gets 50 percent today, he or she will enter Congress immediately. If no one hits the 50 percent mark, the top finishers from each political party advance to a runoff on Dec. 6.

That could produce an interesting scenario if Campbell is the Republican nominee. Gilchrist, as the only candidate of the American Independence Party, is guaranteed a place in the runoff if there is one. If two strong conservatives are on the ballot, that could provide a longshot opportunity for the Democrats to steal the seat. Attorney Steve Young is considered the leading Democratic candidate.