The republicans lost in some historically strong GOP areas. In Orange County, John Wayne country, several seats that the GOP felt were safe and would never go Dem folded up as the GOP was routed in these areas. A number of these contests pitted incumbents-let's not forget Rohrbacher who held his seat for decades-against Dems. Historically a retiring republican simply endorsed his GOP newcomer and the election was as good as over. Not all of these elections can be credited to changing demographics. Newport Beach, Irvine, etc, are very white and were tired of the bullshit. But, yes, in other areas it was a mixed bag.