The Republican presidential contest entered a new phase on Sunday as the campaigns descended on Florida for the first primary in which all the candidates are participating full force, using as their stage a state famous for divisive election battles.  

Four major candidates - Senator John McCain, Mitt Romney, Rudolph W. Giuliani and Mike Huckabee - all have a claim to different segments of the Republican electorate in this culturally and geographically diverse state.  

And in a rare moment of political consensus, all of the campaigns see the Jan. 29 primary in Florida, the fourth most populous state in the nation, as the most important contest on the calendar to date. It is the gateway - candidates hope it is a springboard - to what will in effect be a national primary on Feb. 5, when more than 20 states will hold Republican nominating contests.

Republican Field Rides Full Force Into Florida Test