The stage is set for the first major Republican presidential debate of the 2012 season tonight in Manchester, N.H. -- and candidates are starting to assume roles. Here is a look at who will be on the stage, who won't, and what to expect.

The GOP front runner -- Mitt Romney is the man to beat. The former Massachusetts governor, who failed to secure the nomination in 2008, is better recognized than any of the other Republican candidates who will be on the stage Monday. He is thought to be raising money at a blistering pace.