Who would run if Bush wasn't the nominee? Who will run in the future? Not many names jump out.
Some possibilities:
Powell and Guiliani - both have somewhat liberal social views causing problems with the base, and Powell may become tainted by the Iraq war.
Bill Frist
Gov. Bill Owens (CO) - didn't he recently have a messy divorce.
Chuck Hagel
John McCain
Not too many names jump out, and many have minuses. The Dems. seem to have a deeper bench.
Just something to kick around and a break from the primary stuff.