He’s relying on the several more-conservative candidates (Thompson, Romney, Hunter) splitting the conservative vote and getting the nom on the RINO vote.
By the time the convention rolls around there may be several still running but only 2 viable candidates. The early primaries will probably knock out all except Rudy, Fred and Mitt. Anyone still hanging around is doing do so with an eye toward 2012...or for cash like Keyes did.