Hardly. Crossover Rats are responsible. The same outcome would’ve been achieved had Fred been in the race or not. The result wouldn’t have mattered anyway, Fred wouldn’t have beaten Zero any more than Juan McQueeg did. Jesus Christ Himself wouldn’t have beaten Zero in 2008, even if He ran as a liberal.
Fred Thompson's fan dance kept other conservatives from developing any momentum. Once he was in to divide the vote, he waited until McCain was a lock and bowed out.