Rudy Giuliani is scheduled to make a campaign appearance with Marco Rubio Monday in Miami, and Twitter was running wild on Friday that this means the former New York City Mayor will endorse the former House Speaker in the Republican U.S. Senate race.

No doubt it will be a blow to Charlie Crist if this does happen, but after Giuliani's embarrassing presidential race in 2007-2008, should it be considered that big of a blow?

Readers of the #1 best-seller Game Change (and also Dan Balz and Haynes Johnson's excellent book on the '08 campaign, The Battle For America 2008) no doubt will think this is payback for Crist endorsing John McCain, and not Hizzoner, before the crucial Florida Primary on January 29, 2008.

Unlike Giuliani, McCain did endorse Crist in his 2006 GOP gubernatorial campaign against Tom Gallagher, and McCain expected reciprocation. Or, as depicted in Game Change,