Former Republican Florida Gov. Charlie Crist announces that he is running for the U.S. Congress during a news conference Tuesday, Oct. 20, 2015, in St. Petersburg, Fla. Crist hopes new congressional districts ordered by the Florida Supreme Court will give him a good chance to win. (AP Photo/Chris O'Meara)
Democratic challenger and former Florida Gov. Charlie Crist was left standing alone prior to a debate with Florida Republican Gov. Rick Scott when Mr. Crist insisted on having a fan onstage to keep him cool during the meeting. Candidates are now agreeing on terms of debates prior to taking the dais. (Associated Press)
Democratic candidate Charlie Crist, left, and Republican Gov. Rick Scott shake hands before their live television debate, Tuesday, Oct. 21, 2014 hosted by WJXT-TV and CNN at the Channel 4 studios in Jacksonville, Fla. (AP Photo/The Florida Times-Union, Will Dickey, Pool)
Former Florida Gov. Charlie Crist waves after visiting a phone bank, Monday, Aug. 25, 2014, in Fort Lauderdale, Fla. Crist is running against opponent Nan Rich for the democratic nomination for Florida Governor. Florida's primary election is Tuesday. (AP Photo/Lynne Sladky)
Florida Democratic gubernatorial candidate Charlie Crist speaks at the Florida Press Association and Florida Society of Newspaper Editors at a gubernatorial forum in Coral Gables, Fla., Thursday, July 10, 2014. (AP Photo/Alan Diaz)
Former Florida House Speaker Marco Rubio (left) and Gov. Charlie Crist were cordial to each other earlier this month, but some supporters of Mr. Rubio's Senate bid are angry at the NRSC for favoring Mr. Crist.
Former Republican Gov. Charlie Crist signs a copy of his book before he speaks to the Forum Club of the Palm Beaches in West Palm Beach, Fla., Monday April 14, 2014. Crist aspires to return as governor as a Democrat. (AP Photo/Matt Sedensky)
FILE - In this Thursday, Oct. 25, 2012 file photo, former Florida Gov. Charlie Crist gestures to supporters before a campaign speech by President Obama in Tampa, Fla. Three years after leaving the Florida governor’s mansion and losing a U.S. Senate campaign, Charlie Crist is plotting a political comeback. The man who once identified himself as a Ronald Reagan Republican is gearing up for another gubernatorial bid as a Barack Obama Democrat. (AP Photo/Chris O'Meara, File)