Michele Bachmann, 55
Known for her conservative Tea Party politics
Newt Gingrich, 68
Known for his position as the head of the anti-Clinton Republican wave in 1994.
Jon Huntsman, 51
Salt Lake City, Utah
Known for being a center-right conservative.
Gary E. Johnson, 58
Taos, New Mexico
Known for being the former governor of New Mexico.
Ron Paul, 76
Known for mix of Republican and Libertarian political views.
Rick Perry, 61
Paint Creek, Texas
Known for being elected governor of Texas in 2000.
Buddy Roemer, 68
Known for being the former governor of Louisiana.
Mitt Romney, 64
Known for being governor of Massachusetts and making a run for the Republican presidential nomination in 2008.
Rick Santorum, 53
Great Falls, Virginia.
Known for winning election to the U.S. House of Representatives in 1990.