Where did you get the "data" that republicans stay home because they know they will lose in california? One could more accurately make the argument that many democratic voters stay home because they know their candidate is sure to win anyway.
Many counties in california are extremely republican, particularly the rural ones. They all seem to turn out for the congressional races... in fact, Congressional District One is so violently red that it has often voted in rank carpetbaggers. McClintock got elected in the 1 a few years ago (prior to redistricting) and he had never even set foot in it, due to blind republican party loyalty. You would be better served to back up your projective bullshit with facts or else go post on the conservative fact-free boards.