ABC News' Jake Tapper and Rick Klein Report: Rudy Giuliani will board a plane to California on Wednesday morning, as planned. But, sources tell ABC News, once there, instead of participating in the GOP debate, he will drop out of the presidential race and endorse Sen. John McCain, R-Ariz.Giuliani came down to greet supporters at the Loews Portofino Bay Hotel in Orlando. Responding to a friendly cheer from the audience, Giuliani laughed and quoted "that famous philosopher Yogi Berra, 'It's not over until it's over.'"But it appeared over."Like most Americans, I love competition. I don't back down. . . but there must always be a purpose," Giuliani told supporters as his poor third-place showing became clear on the widescreen TVs. "Elections are about a lot more than candidates."Negotiations between the two campaigns had been ongoing as Florida returns came in, with ABC News and other organizations projecting a McCain win in the Sunshine State."We ran a campaign that was uplifting," Giuliani said, not officially leaving the race but speaking in the past tense. "The responsibility of leadership doesn't end with a single campaign."Giuliani has made clear throughout the campaign that if he weren't running, he would most likely be supporting McCain for president.