His is a district that had been Democratic for a century. Cao is as conservative as you're going to get there. He is also one of the few non-white Republicans in Congress. They should be happy to have Cao.
If the Republicans or activists are foolish enough to put someone against him because he's not "conservative enough" than I might just stop voting for them. (I'm independent, but generally vote Republican) I actually felt it made sense in New York's 23rd as that was a traditionally conservative district, but it makes no sense here.
Granted being a Pro-Life "liberal on race" Catholic maybe effects my views some. Cao was maybe tricked, but I think he likely really does hope this may actually reduce abortion or at least be abortion-neutral. I think he may even be right as I've seen grumbling about it from Pro-Choicers.
Anyway he has voted with his party less than most, but he's still voted with the House Republicans about 80% of the time. He's fairly moderate, but he's more Republican on some terrorism and small business issues. Also on abortion.
http://projects.washingtonpost.com/c.../party-voters/