Former Sen. Rick Santorum of Pennsylvania put his presidential campaign on ice Tuesday, removing the final major hurdle for Mitt Romney to win the Republican nomination and turn his full attention to a general-election bid against President Obama.
Mr. Romney told voters at a town-hall meeting in Delaware that he can now start to think about setting up a process for choosing a vice-presidential nominee, though he said he doesn’t have a list of names.
Rep. Ron Paul of Texas and former House Speaker Newt Gingrich vowed to stay in the race, and each made an appeal to Mr. Santorum’s supporters Tuesday afternoon. But with both men trailing far behind in the delegate count, analysts said, Mr. Santorum’s decision marks the unofficial end of the primaries.
“This has been a good day for me,” Mr. Romney said.
Mr. Santorum’s exit also opened the floodgates for more party leaders to endorse Mr. Romney. Sen. Patrick J. Toomey of Pennsylvania and Govs. Bobby Jindal of Louisiana, Rick Scott of Florida and Terry Branstad of Iowa threw their support to the former Massachusetts governor.
Surrounded by his family, Mr. Santorum said he spent the weekend thinking about priorities after his daughter Bella was hospitalized Friday. She suffers from Trisomy 18, a rare genetic condition that makes illnesses such as pneumonia life-threatening. She was released from the hospital Monday.
“We will suspend our campaign effective today,” Mr. Santorum said at an event in Gettysburg, Pa., promising that he will continue to fight for conservative values and to help Republicans try to defeat Mr. Obama in November.
His move now sets up a scramble for Mr. Romney, who still has work to do in consolidating conservative voters’ support even as he begins to try to reach out to independents who, polls suggest, have soured on him.
Mr. Santorum won nearly 28 percent of all the votes cast in the Republican primary so far, accounting for more than 3.2 million voters. Mr. Romney, in comparison, has won 4.6 million, or about 40 percent.
Michael McKenna, a Republican pollster, said he will be watching polling during the next few weeks to see what happens to those millions of Santorum supporters.
“I’m willing to bet that a pretty significant chunk of the Santorum vote is simply going to exit the process or they’re going to show up and vote for the Senate and congressional races, governors races if they have them, and not hang around to vote for president,” Mr. McKenna said.
He also said to watch for what key members of Mr. Santorum’s organization do, and to keep an eye on high-dollar donors, including billionaire Sheldon Adelson, who was backing Mr. Gingrich’s bid, and Foster Friess, a Santorum backer whose net worth has been estimated at more than a half-billion dollars. If they begin to back Mr. Romney, it will signal that the Republican Party is uniting around him.
On Tuesday afternoon, Mr. Friess told Politico that while he was still considering the details of how to best back Mr. Romney, “I’m obviously going to be of help in whatever way I can.”
One pro-life group, the Susan B. Anthony List, said its activists had been energized by Mr. Santorum’s bid, but that they remain committed to defeating Mr. Obama in November — which could provide a boost for Mr. Romney.
Jim Manley, a Democratic strategist, said he thinks Mr. Romney will do what he needs to do to appeal to his base, just as Mr. Obama has done in his party.