If Republicans can keep the white vote at about 60/40 while getting at least 35% of the Hispanic vote, they have a shot.
Because party activists, left and right - have this view that the country is actually really more like them and less like their opponent and the answer is to elect someone MORE like them. Hence people screeching that Romney lost because he wasn't conservative enough or the Democrats need to shift further to the left.
When again, while politics is very polarised, that doesn't mean the electorate is, especially at the Presidential level. The issue is to win your own people and enough of the middle-ground. Considering the middle-ground of American politics HAS shifted leftwards in recent years, the GOP is in a really, really dangerous position. There isn't a SINGLE GOP candidate who can demonstrate they can win over the middle ground. It's not about personality or who someone is married to, but policies.
No,
the electorate is becoming more polarized, and more so at the presidential level. There's just an ever decreasing amount of swing and cross-over voters, making them look more important.