John McCain’s candidacy was left for dead this summer. But the Republican race is so fluid that there is a chance, a slight chance, that his fortunes can be revived.

Remember the old saw that senators can’t be elected president? The Democratic race is not following that script; senators are dominating.

But look a little closer and you realize that the top three candidates are not running as senators. Hillary Rodham Clinton (N.Y.) is helped by her time in the Senate because she has won her own elective office. But Clinton is running more like an incumbent president than a senator. She did spend eight years in the White House. Barack Obama (Ill.) is running as an outsider, an above-politics newcomer, not an experienced senator. And as for John Edwards (N.C.), his Senate career has receded so far into the past that it is barely noticed. The only Democrats running as senators are the very experienced Joseph Biden (Del.) and Chris Dodd (Conn.), and their electoral prospects are as dim as the myriad of senators who have run for president before them.

On the Republican side, John McCain’s (Ariz.) demise leaves a former mayor atop the race, a couple of former governors who will do well in Iowa and a former senator, who is better known for his career as a district attorney on television.

McCain has been hurt by his image as a senator. Mayors and governors can bash Washington from the outside. They can point to their leadership roles in executive positions. Senators are seen as part of the problem.

McCain’s fall from front-runner status had several causes. First, for several years he was a critic from the right of President Bush on Iraq, an advocate of more boots on the ground. When Bush announced his surge, McCain looked less independent in backing an unpopular president with an unpopular war. McCain and Bush also joined forces on immigration against much of the Republican base. Finally, McCain planned for a gold-plated campaign with gobs of cash, and found himself hemorrhaging money and scaling back. It is not a good sign when late-night comedians joke about his hitching rides to campaign stops.

But McCain has righted his ship somewhat. The surge has not changed overall opinion about the war, but McCain’s forceful defense of the surge’s recent successes reminds us of his heroism. McCain’s life story dwarfs those of the other candidates, and anything that keeps his sacrifice to his country in the forefront helps him. The immigration issue is still a problem for McCain, but at least it is not on the Senate floor day after day. Finally, a new frugality on the campaign trail reminds voters of the 2000 McCain, who did not run as a senator, but as an outsider, a maverick, a straight-talking hero.

All this being said, McCain’s chances are pretty slim, except for the fact that the Republican race is so open.

McCain’s hope is to surprise in New Hampshire, as he did in 2000. With a good chance that Mitt Romney will win in Iowa, Rudy Giuliani will be looking for a win to bounce back in New Hampshire. Romney leads in most polls in New Hampshire, with Giuliani second and McCain a close third. McCain’s maverick message can still play well in the Granite State. McCain need not win, but if he beats out Giuliani for second place, he will give himself the shot to be the less conservative alternative to Romney.

If McCain pulls it all off, it will be not because of his position in the upper chamber, but because he is the heroic, straight-talking maverick.

Fortier is a research fellow at the American Enterprise Institute.