Incumbent Chambliss has enlisted prominent party leaders to campaign for him over the next four weeks — including McCain, Palin, Romney, Huckabee, Gingrich and Giuliani.

And/But: Democrat Jim Martin is pushing for Obama to campaign for him in the state.

The run-off will be held Dec. 2 if neither candidate gets 50% of the vote when all the ballots are counted. Current tallies: Chambliss 49.8%, Martin 46.8%.