Santorum suspends bid, clears path for Romney

Santorum’s decision allows Romney to begin the urgent task of trying to heal the wounds from a divisive and sometimes brutal primary while broadening his appeal to independents who will be crucial to his effort to defeat President Obama in the fall.

Santorum had proved to be the fiercest challenger to Romney’s claim on the nomination, in a campaign season that has seen that mantle pass repeatedly from candidate to candidate. But he was ultimately overmatched in money and organization, and it would have been nearly impossible for him to collect the 1,144 delegates needed to secure the nomination.

“While this presidential race for us is over, for me, and we will suspend our campaign today, we are not done fighting,’’ Santorum said, vowing to turn his attention to defeating Obama in November. Santorum gave no specific reason for dropping out, but pointed to the hospitalization over the weekend of his daughter, Bella, who was born with a rare genetic condition.

He did not offer an endorsement, or any mention, of Romney.

The former Massachusetts governor - fulfilling a dream his father, George, sought but never realized and one that he has pursued for years - becomes the de facto nominee with all the advantages and risks that title carries.

He emerges from the long primary season a bruised candidate, with high unfavorability numbers and questions over his vast wealth and political authenticity that the Obama campaign is eager to exploit. But no longer will Romney need to expend valuable campaign cash on television ads fighting his Republican rivals.

His campaign staff - and his Boston headquarters - can begin to focus on about a dozen crucial swing states, rather than sending a handful of aides scurrying from primary to primary trying to woo recalcitrant conservatives. Romney may also find himself in more comfortable territory trying to appeal to independent voters rather than seeking to win over conservative Republicans.

At the same time, he now leads a party that has yet to fully embrace him. In an election that has been marked by who could emerge as the anti-Romney, the party must now become pro-Romney, whether its base is ready to or not.

Republican leaders seemed to greet Santorum’s exit with a measure of relief, hoping that the voters can now begin to unite behind Romney.

“We were in this strange environment where there was no national Republican leader who could drive the agenda,’’ said Mike Dennehy, an adviser to John McCain’s 2008 presidential campaign. “Now we have that in Mitt Romney.’’

Polling data sent a clear message that Romney needed to end the primary campaign. “Attacks on both sides are being lobbed every day, and they are impacting his numbers,’’ Dennehy said. “It’s only going to help him where he can get into a general election environment and focus on Obama and swing votes in battleground states.’’

Those swing votes become a paramount concern. During the primaries, Romney took strong stances against such issues as requiring insurers to cover contraceptives and finding a way toward citizenship for illegal immigrants. His use of harsh rhetoric has hurt his standing among some female voters and could hinder his attempts to win over the growing numbers of Hispanic voters in swing states such as Nevada, New Mexico, and Colorado.

Santorum’s decision also frees Romney’s campaign to redirect its spending toward attacking Obama. By the end of February, Romney had spent $67.3 million on the primaries and a super PAC supporting him, Restore Our Future, had spent $32.7 million.

His campaign had $7.3 million in the bank, a sum dwarfed by the Obama campaign’s $84.7 million, according to the most recent federal campaign finance reports. However, super PACS supporting Romney and conservative issues have already begun attacking Obama in several key states.

In a somber address in his home state of Pennsylvania, Santorum said that although his daughter is improving after a bout of pneumonia, the illness had prompted him and his wife, Karen, to rethink whether to continue the campaign.

He was facing the possibility of a humiliating loss in Pennsylvania on April 24, a blow that would have followed a trio of losses in the last round of primaries, in Wisconsin, Maryland, and Washington, D.C., last week. Political analysts have said another loss in Pennsylvania - he was soundly defeated in his bid for reelection to the Senate in 2006 - would dim any chances he would have of running again for the presidency.

In his roughly 13-minute speech at the Gettysburg Hotel, Santorum drew a contrast between what he described as his positive message focused on family values and economic concerns and the nastiness shown by his rivals.

“We weren’t out there trashing anybody,’’ Santorum said. “We painted a hopeful, positive vision for our country.’’

And, he added, “Against all odds, we won 11 states.’’

Romney praised his rival in a speech to supporters in Wilmington, Del.

“He has made an important contribution to the political process, has brought forward issues he cares deeply about, and has been able to gather a great deal of public support and interest in those issues and in himself,’’ he said. “He will continue to have a major role in the Republican Party, and I look forward to his work in helping assure victories for Republicans across the country in November.’’

The Obama campaign immediately seized on Santorum’s exit to once again attack Romney, underscoring how both camps have already shifted their focus toward the general election.

“It’s no surprise that Mitt Romney finally was able to grind down his opponents under an avalanche of negative ads,’’ Jim Messina, Obama’s campaign manager, said in a statement. “But neither he nor his special interest allies will be able to buy the presidency with their negative attacks. The more the American people see of Mitt Romney, the less they like him and the less they trust him.’’

Santorum had been waging an uphill fight since the moment he entered the race. In the run-up to the primaries, he toiled in obscurity, often the candidate at the end of the stage in a series of early debates. He rode a vigorous campaign in Iowa to a surprise win in the first-in-the-nation contest in January.

Romney, with his vast fund-raising machine, deep base of establishment support, and sophisticated campaign operation, remained the favorite to lock up the nomination.

But Santorum effectively marshaled doubts about Romney’s fidelity to conservative principles, and skepticism toward Romney among evangelicals and social conservatives, into a potent political force. Calling himself a “guy from a steel town,’’ he cast himself as the voice of blue-collar voters who were reluctant to embrace the wealthy former governor of Massachusetts.

At one point, he was close to defeating Romney in his native Michigan.

“There were moments; he was a handful of votes away from making this a genuine barn-burner,’’ said Henry Barbour, a Romney supporter and Republican National Committee member from Mississippi. “Romney was able to avoid that. But it was a tough race, and it was almost a lot closer than some may realize.’’

Santorum also left a record of harsh attacks on Romney. He called him “the worst Republican in the country to put up against Barack Obama’’ and “uniquely unqualified’’ to represent the party because of the similarities between the Massachusetts health care law and the national version signed by Obama.

Newt Gingrich and Ron Paul are looking ahead to speaking roles at the party’s convention in Tampa in August.

“I am committed to staying in this race all the way to Tampa so that the conservative movement has a real choice,’’ Gingrich said Tuesday, asking for the support of Santorum’s backers.

Michael Levenson can be reached at mlevenson@globe.com; Matt Viser can be reached at maviser@globe.com