In a video from the Horatio Alger Association, William Doré tells of a tense and abusive childhood. Horatio Alger Association/YouTube hide caption

Rick Santorum speaks in Mars, Pa., on Tuesday, after Mitt Romney swept primaries in Wisconsin, Washington, D.C., and Maryland. In his speech, Santorum declared that it's "halftime" in the race for delegates and the GOP nomination. David Maxwell/EPA/Landov hide caption

Rick Santorum speaks Wednesday in Hollidaysburg, Pa., holding boxing gloves given to him by Pennsylvania State Sen. John Eichelberger (left). On Thursday, Santorum met in private with a group of conservative leaders to discuss next steps in his campaign. Paul J. Richards/AFP/Getty Images hide caption

The action was in Wisconsin Tuesday night, but Rick Santorum and his wife, Karen, had already moved on to his home state of Pennsylvania. They greeted supporters at an election night rally in Mars. Jason Cohn /Reuters /Landov hide caption

Republican presidential candidate, former U.S. Sen. Rick Santorum speaks at a campaign rally at Four Seasons Sheraton in Mars, Pa., Monday night. Rival Mitt Romney won the Washington, D.C., Maryland and Wisconsin primaries. Jeff Swensen/Getty Images hide caption

Rick Santorum won the Louisiana Republican presidential primary Saturday, beating front-runner Mitt Romney in the race to challenge President Obama. Jae C. Hong/AP hide caption

Republican presidential candidate, former Sen. Rick Santorum, speaks at a campaign rally in West Monroe, La. on Friday. Ben Corda/AP hide caption

Rick Santorum told voters in Mandeville, La. on Wednesday that they were "not looking for someone who's the Etch A Sketch candidate." Sean Gardner /Reuters /Landov hide caption

After Rick Santorum won primaries in Alabama and Mississippi on Tuesday, he addressed supporters in Louisiana, which holds its primary on March 24. Sean Gardner/Getty Images hide caption

Rick Santorum addresses supporters on Tuesday in Lafayette, La. Sean Gardner/Getty Images hide caption

Supporters of Rick Santorum, organized by the anti-abortion Susan B. Anthony List, spoke outside the Georgia State Capitol on March 5. AFP/AFP/Getty Images hide caption

Former Pennsylvania Sen. Rick Santorum and his wife, Karen, greet supporters during a rally Saturday in Springfield, Mo. After picking up a decisive win in Kansas, Santorum now turns his attention to Missouri's upcoming caucuses. Whitney Curtis/Getty Images hide caption

Republican presidential candidate Rick Santorum addresses an election night party in Steubenville, Ohio, on Tuesday. Jim Watson/AFP/Getty Images hide caption

Then-Sen. John F. Kennedy participates in a question-and-answer session with the Ministers' Association of Greater Houston on Sept. 12, 1960, in Houston. In a speech to the group, Kennedy addressed concerns about his Catholicism and his run for the presidency. Houston Chronicle/AP hide caption

On the campaign trail, Rick Santorum portrays himself as a Washington outsider. But the former senator has made money from inside-the-Beltway pursuits. Jeff Kowalsky/EPA/Landov hide caption

Republican presidential candidate Rick Santorum, center, and supporters as they prayed earlier this month in McKinney, Texas. Tom Pennington/Getty Images hide caption