AUBURN -- A staunchly conservative state senator from Southern California is jumping into a Northern California congressional race.

Senator Tom McClintock of Thousand Oaks announced Tuesday that he will run for the Republican nomination for the seat now held by Representative John Doolittle, a Republican from Rocklin.

Doolittle is under investigation in the congressional lobbying scandal. He announced in January that he would not run for a 10th term in the House of Representatives.

McClintock's entry into the race promoted another Republican, former state Senator Rico Oller of San Andreas, to drop out.

Former Representative Doug Ose also is running in the GOP primary.