If Al Gore had won West Virginia (like everyone expected him to) he would be President.
While people point out his environmental positions and opposition to guns contributed to this, they are ignoring the role Byrd played.
Basically, for whatever reason (he just doesn't like the guy I guess) Byrd refused to endorse or offer an organizational support to Gore until LATE in the game.
Now... Bush is polling horribly in AZ. There are a lot of seniors there would won't be pleased with his health care efforts. And McCain is no Bush fan. If McCain withholds his active support, it could lead to Bush's defeat (though, if McCain makes a point of campaigning for Bush he'll carry AZ).
And there is no way Bush can with without AZ.