Rick Santorum is a former member of the House of Representative (1991-1995) and the US Senate (1995-2007), representing the state of Pennsylvania. He lost his Senate re-election campaign in 2006 as well as his bid for the Republican presidential nomination in 2012, where he finished as the runner-up after Mitt Romney.

Age: 57 (born May 10, 1958)

Campaign: Rick Santorum for President

Main political views: A social conservative with strong opposition towards same-sex marriage and abortion. Santorum is also very religious as a devout Catholic, which provides him some support from the Christian right faction of the GOP.

Chances of winning: Although Santorum finished second in the last race for the Republican nomination, his chances seem very small for the 2016 nomination. He seems to be too far behind the front-runners this time around and like many candidates in the Republican field, he lacks poll-numbers and media attention to change that fact.

Update: Rick Santorum became the 4th candidate to drop out of the race in the days after the Iowa caucus after only getting 1% of the votes. Santorum won the caucus in 2012. Soon after his withdrawal, Santorum endorsed Marco Rubio.

(Photo credit: Gage Skidmore)