FILE - In this Feb. 11, 2011 file photo, former Massachusetts Gov. Mitt Romney addresses the Conservative Political Action Conference (CPAC) in Washington. Ready or not, the 2012 presidential campaign is under way in earnest a full 18 months before Election Day. The GOP field — still muddy and made up of no less than a dozen people — will become clearer in coming days as more Republicans declare they'll run or sit out — and President Barack Obama's schedule already is packed with fundraisers and visits to states important to his re-election chances. (AP Photo/Alex Brandon, File)AP – Republican Gov. Haley Barbour bowed out of presidential contention Monday with a surprise announcement just as the 2012 campaign was getting under way in earnest, 18 months before Election Day. The Mississippi governor said he lacked the necessary “absolute fire in the belly” to run.