False assumption.
Just because somebody votes republican doesn't mean they're a conservative, and just because somebody votes democrat doesn't mean they're a liberal. There are plenty of people in both parties who are just ignorant and pull the level for a party and have no idea what the party or the candidate stands for.
However, on the whole, rural areas tend to be more Republican and more conservative and cities more Democratic and more liberal, because most liberals are Democrats and most conservatives are Republicans.
It was a somewhat similar situation in 1980, but still less rural-urban divide.
Just look at Dukakis vs. Bush, 1988:
Compare it to Kerry vs. Bush II: The Rebushining, 2004:
Poll
