An excerpt from the new Veep Diary:

Still, Romney is an unquantifiable here. I mentioned yesterday that if McCain were to pick Ridge, “it will be because he likes him personally and believes Ridge can win Pennsylvania.” Now, it’s not clear to me that McCain will make the choice based on whether a veep could carry a particular state, but if he did, I’ve been told, there is a feeling that Romney has a pretty good argument to make that choosing him would help quite a bit in Nevada and Colorado, with their significant Mormon populations. That makes some sense; it’s my guess that Romney could do more to bring in Nevada and Colorado than Ridge could in Pennsylvania.