Rick Santorum (AP)

GETTYSBURG, Pa. (AP) -- Bowing to the inevitable, Rick Santorum quit the presidential campaign Tuesday, clearing the way for Mitt Romney to claim the Republican nomination.

Santorum, appearing with his wife and family in his home state of Pennsylvania, told supporters the race for him was over, but the fight to defeat President Barack Obama would go on.

Santorum made no mention of Romney, and stressed that he'd gone farther than anyone expected, competing "against all odds."

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