In it, but not of it. TPM DC
"Whether I did have a history or not with Gov. Crist, in terms of him having broken his word, I'd be supporting Marco in any event," Giuliani said, calling Rubio "the future of our party."
Rudy also added: "Marco has shown throughout his career that he can be trusted."
According to the Mark Halperin/John Heilemann book Game Change, Giuliani ended up banking his whole campaign on winning Crist's endorsement in the Florida primary, and the two camps had engaged in very close negotiations. And at some point, Rudy appears to have genuinely thought he would get the coveted endorsement.
But in the end, Crist ended up going for John McCain, who was on his way to the Republican nomination. Giuliani ended up getting only 15% of the vote in the Florida primary, and he dropped out the next day.