Former Senator Rick Santorum of Pennsylvania began a campaign for the 2012 Republican Party nomination for president of the United States in April 2011.

Santorum lagged in the polls for all of 2011 until he surged in the week before the Iowa caucuses, propelling him to a narrow victory over Mitt Romney in the first contest of the presidential primaries.

Santorum's presidential hopes received another boost when he surprisingly swept all three votes held on February 7, 2012, in Minnesota, Missouri, and Colorado.

Santorum filed for an exploratory committee with Federal Election Commission, and announced the organization on the Fox News program On the Record w/ Greta Van Susteren on April 13, 2011.

[5] He formally announced his run for the Republican presidential nomination on ABC's Good Morning America on Monday, June 6, 2011.

"[6] Santorum suffered from poor fund-raising and weak ground operations, and the viability of his campaign was in doubt during the Ames Poll.

[10] Although he was considered a "joke" candidate and panned as unelectable in some quarters, his solid consistency among fellow anti-abortion Catholics kept him in the race.

[18] Santorum's candidacy was compared to that of Mike Huckabee, who surprisingly won Iowa despite similarly poor performance in the polls.

The Washington Times reported in November 2011 that conservatives had gone on a "carousel" of supporting different candidates against Mitt Romney, from Michele Bachmann to Rick Perry to Herman Cain to Newt Gingrich.

Santorum said Gingrich's Contract with America was overrated and took too much credit from the Gang of Six, of which he was a part, which exposed congressional banking corruption in 1994.

[19] Santorum also gained the confidence of several evangelical religious leaders and Sarah Palin for his "ideological consistency".

[20][21] In December 2011, Santorum's poll numbers in Iowa remained low, but he attracted more attention as a dark horse candidate, and said Iowans were beginning to respond to his message.

"[22] He urged Iowans not to go along with the polls and the pundits, who have pitted the race as being between Mitt Romney and Newt Gingrich, but to lead the national conversation by picking him, an underdog.

[23] There were complaints about a statement made in Sioux City, Iowa, when Santorum said, "I don't want to make black people's lives better by giving them somebody else's money".

Sioux City conservative talk radio host Sam Clovis cited Santorum's beliefs in "a constitutionally limited government, fiscal responsibility, strong national defense and unflagging devotion to life and traditional marriage.

"[31] Other endorsements included Iowa Secretary of State Matt Schultz,[32] Cornerstone Church pastor and evangelical leader Cary Gordon,[20] and bestselling thriller novelist Brad Thor.

However, the paper noted, "the four-day results don't reflect just how quickly momentum is shifting in a race that has remained highly fluid for months.

[44] On January 14, 2012, during the run-up to the South Carolina primary, Santorum won the endorsement of the Family Research Council, a group of 150 social conservative leaders who held an emergency meeting to determine the best social conservative candidate to coalesce around to beat Romney.

Santorum edged out Romney by 5 points in the Colorado caucuses in a significant upset,[52] beat second-place finisher Ron Paul by 45% to 27% in the Minnesota caucuses, and dominated the Missouri primary, defeating Romney 55%–25% in a contest that did not include Newt Gingrich on the ballot and did not assign any delegates.

[53][54] Two days before the vote Public Policy Polling (PPP) had suggested that Santorum would finish second in Colorado, face a close contest with Romney and Gingrich in Minnesota, and win by a smaller margin in Missouri.

[72] Santorum's campaign said the committee, which was composed mostly of Romney supporters, was trying to fix the primary because it didn't like the results of the popular vote.

Some prominent Republicans had voiced concerns over Santorum's ability to win female voters, given his conservative views on contraception.

[78] Santorum said his 11th victory sent shockwaves through the political world as he continued to win in the South, Midwest, and West.

"[79] Despite big wins in the South in March, after Romney's victory in Illinois the media painted a dim picture about Santorum's road ahead, as Romney's big lead in the delegate count after several early state wins was close to insurmountable.

Santorum was also running low on cash, while Romney continued spending millions of dollars per state to edge out victories.

"[80] At a campaign event in Wisconsin on March 26, Santorum angrily told the crowd, "Pick any Republican in the country!

The Los Angeles Times wrote, Largely ignored as he drove past the cornfields of Iowa in a pickup, Santorum doggedly met with voters at diners, farms and county fairs.

That work paid off in a surprise win in Iowa and in 10 other states as he became the physical manifestation of the GOP base's unhappiness with Romney.

Santorum's ill-funded team had neither the resources nor the organization for important basics like filling slates of delegates, meaning that even in states he won he could not fully shake Romney.

Santorum's decision came as key GOP figures had begun to coalesce behind the former Massachusetts governor, arguing that it was time for the party to focus on beating Obama.