Rick Santorum campaigns in WisconsinMark Hirsch/Getty Images
Rick Santorum is suspending his campaign for the GOP presidential nomination, clearing a path for Mitt Romney to become the nominee. Santorum faced a tough fight in his home state of Pennsylvania against Romney.
The slideshow above shows scenes from Santorum's presidential bid.
Gallery
Republican presidential candidate, former U.S. Sen. Rick Santorum holds up an Etch-A-Sketch as he speaks to supporters at a "Rally for Rick," at Ledgeview Bowling Lanes on March 25, 2012 in Fond du Lac, Wisconsin.Mark Hirsch/Getty ImagesView full galleryRepublican presidential candidate, former U.S. Sen. Rick Santorum (R) chats with Mayor Dale Oppermann outside Wedl's Hamburger Stand during an impromptu campaign stop on March 27, 2012 in Jefferson, Wis. Wisconsin residents will go to the polls on April 3 to vote for their choice for the Republican presidential nominee.Scott Olson/Getty ImagesRepublican presidential candidate, former Sen. Rick Santorum (R-PA) delivers remarks in front of the Supreme Court on the first day of oral arguements in the Patient Protection and Affordable Care Act March 26, 2012 in Washington, DC. Today the high court, which has set aside six hours over three days, heard arguments over the constitutionality of the act.Mark Wilson/Getty ImagesSupporters listen as Republican presidential candidate and former Pennsylvania Sen. Rick Santorum speaks at a campaign rally on March 19, 2012 in Dixon, Ill. Illinois residents will go to the polls on March 20 to vote their choice for the Republican presidential nominee. Santorum will be watching from a distance, in Gettysburg, Penn.Scott Olson/Getty ImagesRepublican presidential candidate, former Pennsylvania Sen. Rick Santorum, speaks as supporters of fellow Republican presidential candidate Mitt Romney holds up signs for their candidate at Westminster Christian Academy Saturday, March 17, 2012, in Town and Country, Mo.AP Photo/Jeff RobersonRepublican presidential candidate, former Pennsylvania Sen. Rick Santorum gives a thumbs up during his election night party, Tuesday, March 13, 2012, in Lafayette, La.AP Photo/Eric GayRepublican presidential hopeful Mitt Romney attends a Super Tuesday Republican primary elections evening in Boston, Massaschusetts, March 6, 2012. Republican voters made their way to the polls in the Super Tuesday primary elections in 10 states and 437 delegates at stake. AFP PHOTO/Emmanuel Dunand (Photo credit should read EMMANUEL DUNAND/AFP/Getty Images)EMMANUEL DUNAND/AFP/Getty ImagesRepublican presidential candidate, former Pennsylvania Sen. Rick Santorum, center right, kisses his wife Karen before speaking to supporters at an election night party at Steubenville High School in Steubenville, Ohio, Tuesday, March 6, 2012.AP Photo/Gene J. PuskarRepublican presidential candidate, former Pennsylvania Sen. Rick Santorum, arrives to speak before the American Israel Public Affairs Committee (AIPAC), in Washington, Tuesday, March 6, 2012.AP Photo/Charles DharapakRepublican presidential candidates U.S. Rep. former U.S. Sen. Rick Santorum (L) and former Massachusetts Gov. Mitt Romney participate in a debate sponsored by CNN and the Republican Party of Arizona at the Mesa Arts Center February 22, 2012 in Mesa, Arizona. The debate is the last one scheduled before voters head to the polls in Michigan and Arizona's primaries on February 28 and Super Tuesday on March 6.Justin Sullivan/Getty ImagesRepublican presidential candidate, former Pennsylvania Sen. Rick Santorum speaks during a campaign rally at the Sabbar Shrine Center, Wednesday, Feb. 22, 2012, in Tucson, Ariz.AP Photo/Eric GayFormer Pennsylvania Sen. Rick Santorum to a crowd of 150 to 250 supporters just hours before the Minnesota caucus gets underway, Tuesday, Feb. 7, 2012 at the National Sports Center in Blaine, Minn.MPR Photo/Tom ScheckRepublican presidential candidate and former Pennsylvania Sen. Rick Santorum speaks about health care, Monday, Feb. 6, 2012, in Rochester, Minn.AP Photo/Charles Rex ArbogastWayne Stillman, president of the Rochester Veterans Memorial Association, at right, gives Republican presidential hopeful Rick Santorum a tour of Rochester's Veterans Memorial Monday morning.MPR Photo/ Elizabeth BaierRepublican presidential candidate former Pennsylvania Sen. Rick Santorum, center, looks at a display of his official, Santorum for president sweater vest, at the Bemidji Wollen Mills store, with owner Bill Batchhelder, right, during a campaign stop at the vest manufacturer Sunday, Feb. 5, 2012, in Bemidji, Minn.Charles Rex Arbogast/ASSOCIATED PRESSRepublican presidential candidate Sen. Rick Santorum took questions from Senior Pastor Troy Dobbs at Grace Church in Eden Prairie Feb. 5, 2012.MPR Photo/Rupa ShenoyOn the eve of the Florida GOP primary, presidential candidate Rick Santorum campaigns Monday, Jan. 30, 2012, in Luverne, Minn. Santorum told about 300 Minnesota voters who had gathered to hear him speak that their votes weren't paid as much attention as Iowa's, but that they were "just as important."Amber Hunt/ASSOCIATED PRESSPresidential candidate Rick Santorum waits to speak at a campaign rally at The Daily Grind coffee shop Sunday, Jan. 1, 2012 in Sioux City, Iowa.MPR Photo/Jennifer SimonsonSam Clovis, left, a conservative Sioux City radio host, visits with people waiting for a Rick Santorum campaign rally Sunday, Jan. 1, 2012 at The Daily Grind coffee shop in Sioux City, Iowa.MPR Photo/Jennifer SimonsonRepublican presidential candidate Rick Santorum greets supporters and University of Iowa football fans during an Insight Bowl watch party Friday, Dec. 30, 2011 at the Okoboji Grill in Urbandale, Iowa.MPR Photo/Jennifer SimonsonRepublican presidential candidate Rick Santorum greets supporters and University of Iowa football fans during an Insight Bowl watch party Friday, Dec. 30, 2011 at the Okoboji Grill in Urbandale, Iowa.MPR Photo/Jennifer SimonsonRepublican presidential candidates from left, former Pennsylvania Sen. Rick Santorum, Texas Gov. Rick Perry, former Massachusetts Gov. Mitt Romney, former House Speaker Newt Gingrich, Rep. Ron Paul, R-Texas, Rep. Michele Bachmann, R-Minn., and former Utah Gov. Jon Huntsman arrive for a Republican presidential debate in Sioux City, Iowa, Thursday, Dec. 15, 2011.AP Photo/Eric GayRepublican presidential candidate U.S. Rep. Michele Bachmann, R-Minn., speaks during the Thanksgiving Family Forum sponsored by The Family Leader as former Pennsylvania Sen. Rick Santorum, looks on, Saturday, Nov. 19, 2011, in Des Moines, Iowa.Charlie Neibergall/ASSOCIATED PRESS