Krugman (sub.req.) hits it on the nose today:
[I]f the real source of today's bitter partisanship is a Republican move to the right on economic issues, why have the last three elections been dominated by talk of terrorism, with a bit of religion on the side? Because a party whose economic policies favor a narrow elite needs to focus the public's attention elsewhere. And there's no better way to do that than accusing the other party of being unpatriotic and godless.
Thus in 2004, President Bush basically ran as America's defender against gay married terrorists. He waited until after the election to reveal that what he really wanted to do was privatize Social Security.