When U.S. troops are in the field, the candidate perceived as more hawkish always wins. If you can find an instance where this was not the case, let me know. Since I suspect somebody will raise the counterexample of 1968, when Johnson supposedly had his presidency destroyed by a war many times more controversial than the current one, let me show how this election demonstrates my thesis dramatically: We'll never know how LBJ would have done in a general election, but in the event Nixon squeaked by Humphrey (at best a lukewarm antiwar prospect, but in style and substance clearly less hawkish than Nixon). Even in 1972, when public opinion had supposedly shifted decisively against the war and it was clear to all that we were going to lose, Nixon vivisected McGovern-just on the promise of losing it a little more slowly than McGovern would have.

1. We're winning the war, and Bush is perceived as fighting it competently. At that point, his resume would speak for itself.
   
2. We're not winning the war--note that this does not require that we are losing, just that it's not obvious that we're winning. In this case, voters will not "change horses in the middle of the stream", but rally around the president.