GETTYSBURG, Penn. Bowing to the inevitable after an improbably resilient run for the White House, Rick Santorum quit the presidential race on Tuesday, clearing the way for Mitt Romney to claim the Republican nomination.

We made a decision over the weekend, that while this presidential race for us is over, for me, and we will suspend our campaign today, we are not done fighting, he said.

Santorum, appearing with his family, told supporters that the battle to defeat President Barack Obama would go on but pointedly made no mention or endorsement of Romney, whom he had derided as an unworthy standard-bearer for the GOP.

The former Pennsylvania senator stressed that hed taken his presidential bid farther than anyone expected, calling his campaign as improbable as any race that you will ever see for president.

Against all odds, he said, we won 11 states, millions of voters, millions of votes.

Santorum signaled his intent to maintain a voice in the campaign to come, saying: This game is a long, long, long way from over. We will continue to go out and fight and defeat President Barack Obama.

Santorum spoke with Romney before the announcement, a Republican source close to the campaign said, and Romney asked to meet him sometime in the future

The delegate totals told the tale of Santorums demise. Romney has more than twice as many delegates as Santorum and is on pace to reach the 1,144 delegates needed to clinch the nomination by early June. Still in the race, but not considered a factor: former House Speaker Newt Gingrich and Texas Rep. Ron Paul.

Santorum had hoped to keep his campaign going through the Pennsylvania primary on April 24, but decided to fold after his severely ill 3-year-old daughter, Bella, spent the weekend in the hospital.

Santorum, a feisty campaigner who took everyone by surprise with his win in Iowas leadoff caucuses, ran on his conservative credentials and his experience in Congress he was a House member for four years and senator for 12 but was hobbled by a lack of money and organization.

He said that while Romney was accumulating more delegates, we were winning in a very different way. We were touching hearts with a conservative message.

In a statement, Romney called Santorum an able and worthy competitor and congratulated him on his campaign.

He has proven himself to be an important voice in our party and in the nation, Romney said. We both recognize that what is most important is putting the failures of the last three years behind us and setting America back on the path to prosperity.

With Romney on his way to the nomination and a contest against the president, Obamas campaign manager, Jim Messina, sharply criticized Romney for waging a negative ad campaign against his opponents.