The Sunshine State brawl between Gov. Charlie Crist and House Speaker Marco Rubio has suddenly become a national petri dish for the future of Republican politics.
Facing what seems an unwinnable challenge from Tea Party poster child Rubio, Crist is expected to announce at a press conference today that he will run as an independent for the U.S. Senate, setting up what would appear to be a tight three-way race.
Crist had hinted before that he was considering this move.
"I think I'll take the advice of people in Florida instead of the advice of people in Washington," Crist told reporters last week. "They try to tell us a lot, and I don't think we need to listen. ... Things change."
Crist was once the rising star of the GOP -- much like his challenger Rubio is presently. The Republican Party in turn made him one of the most powerful political figures in Florida, but he's since lost that support. Many say the cause of the governor's slipping Republican support was Crist's embrace of President Obama -- literally.
In February 2009, the president visited Florida to promote the economic stimulus program, and invited Crist -- who supported it -- to appear onstage. After Crist finished his remarks, he and the president exchanged a quick embrace that Republican critics quickly seized upon.
More damaging than the embrace itself was Crist's support of the president's stimulus plan, blasted by most Republicans.
Driving Crist to run as an independent is a huge show of the Tea Party movement's power, and a warning shot to moderate, incumbent Republicans. Republicans in Washington have been bracing for Crist to leave the GOP. They tried -- apparently in vain -- to persuade him to remain with the party.
But some Republicans say as the mid-term elections draws closer, candidates are likely to move toward the party's core principles and those like Crist are sure to be left out.
"I think that this has less to do with Crist being a Republican and feeling he has to take this set of Republican principles," Republican strategist Kevin Madden told "Good Morning America's" George Stephanopoulos. "Instead this has more to do with Crist and his political expediency. He cares more about his career than he does about his political party."
A Florida Republican source, who claimed not to have been notified personally of Crist's plans, told ABC News that the internal polling Crist got back this week showed that the only possible path for him to win the Senate seat was to run as an independent. This source was told by Crist's campaign manager that he anticipates Crist will announce an independent bid for the U.S. Senate Thursday.
Democrats hope a split of the conservative vote will help their man, Kendrick Meek.
"Some people feel running against two Republicans is better than running against one," said Rep. Kendrick Meek, D-Fla.
An April 13th Quinnipiac public opinion poll in Florida asked people how they would vote in a three-way race with Crist as an independent. The poll showed a tight contest: Crist with 32 percent, Rubio with 30, and Meek with 24.
Nationally, some Democrats say their prospects in the mid-term elections still do not look strong, but this shows that there are some signs of hope.
"This is still one of the better weeks we've had," Democratic strategist James Carville said on "GMA." "What was shaping up to be an awful year, this week showed that Republicans have their share of problems too."
Charlie Crist Expected to Leave GOP, Run as Independent
The Senate races in Kentucky and Arizona are also spawning bloody Republican primary battles. And in the Texas gubernatorial primary, Washington-bashing Republican Gov. Rick Perry -- another Tea Party darling -- easily crushed Sen. Kay Bailey Hutchison -- once thought a Republican powerhouse.
Some think it may become a prototype for an independent presidential bid in 2012 by somebody like New York Mayor Michael Bloomberg, who may determine it's better to challenge a Republicans by running as an independent.
Party switching is not new or unique. Former Rhode Island GOP Sen. Lincoln Chafee left the party to run as an independent, New York City Mayor Michael Bloomberg went from being a Democrat to a Republican to an independent, Sen. Joe Lieberman switched to independent, and most recently, Sen. Arlen Specter moved from the Republican to the Democratic party.
A Republican source told ABC News that Crist had started calling his major donors to tell them of his decision to run as an independent.
The source says that virtually all of his political staff will leave.
"I'm sure they already have their boxes packed," said the source, who was granted anonymity to encourage candor about the still-evolving situation.
One staffer who is expected to stay on board is Crist's finance director, Dane Eagle. Crist will need him if, as expected, many donors ask for their money back when Crist bolts the GOP.
The source says that a long-time Crist supporter from Tampa named Greg Truax is helping him assemble a new staff.
ABC News' Kristina Wong, Teddy Davis, David Chalian and Gary Langer contributed to this report.