Not more religiously conservative - more vehemently secular. Everyone in America knows where the Church stands on abortion, gay marriage, contraception, and divorce. If a faithful Catholic is elected to the presidency in this climate, it will be at the hand of God.
I suppose a plausible argument could be made that the culture has moved from a conservative protestantism in the fifties to a militant secularism in the oughts, with the 'catholic' president a hiccup along the way. Catholics by and large have absorbed the protestant idea of do-it-yourself theology and distinguish themselves ethically from the rest of the culture not at all.