By Barbara Liston
ORLANDO, Jan 21 (Reuters) - President Barack Obama's 2012 campaign chief, Jim Messina, has joined the Florida gubernatorial campaign of Charlie Crist in a sign that the Democratic party is gearing up for a big political battle to win the state in 2014.
"It signals that the national Democratic Party machinery is going to be behind Crist. It erases all doubts of that," said Susan MacManus, a longtime Florida political analyst and professor at the University of South Florida.
Crist, a one-time Republican governor of the state, is running as a Democrat.
Messina's title is senior adviser, according to campaign spokesman Kevin Cate. A campaign manager has yet to be picked, he said.
Crist's challenge to incumbent Republican Governor Rick Scott, one of 36 gubernatorial contests on the 2014 midterm ballot, is considered by many to be the one to watch.
As the only gubernatorial election in a big swing state, a Democratic victory in November 2014 would be a major upset for the Republican party heading into the 2016 presidential race. Florida's governorship has been under Republican control for 15 years.
"It's a national race. It's not just a state race," said Bob Poe, Obama's former Central Florida finance chairman who now manages Crist's fundraising political committee.
Crist's party switching and reputation for shifting positions on key issues have raised concerns among the rank-and-file about his ability to get the Democrats fully behind him.
Messina is by far the biggest name among several Obama operatives to join Crist, who can also tap into the president's impressive field operations which remained intact after the 2012 election, promoting the launch of the Affordable Care Act, commonly known as Obamacare.
Teddy Goff, digital director for the president's re-election campaign, who oversaw its social media and online advertising efforts, is also joining Crist's campaign.
Crist leads Scott in the polls but lags well behind in fundraising.
Crist is expected to easily win the Democrat primary to challenge Scott on August 26 against former state Senator Nan Rich. (Editing by David Adams and Cynthia Osterman)