McCain has not cared much about the conservative base (far from it, he loathes it). I don’t really think he is calculating on getting many votes from the traditional base and is, instead, going to try to establish a new base (with liberal Republicans and the mushy middle) for himself which may include courting some of the social conservative base while telling the rest of it to get stuffed. We’ll see if it works. No matter who wins, get ready for bigger government (global warming) and amnesty.
Not just a new base, with what he is doing he is shifting the base of ALL politics to the left forever just to get along and this will change the scale of conservatism/liberalism way to the left for good.