"It's unclear how Romney will distinguish himself as a candidate and as a person, other than as a business-minded Republican," Scala said, an image that might not motivate Santorum's supporters to go to the polls in the general election.
Santorum's announcement did not include an endorsement of Romney but that is expected in the coming weeks.
"It usually takes a while for the wounds to heal," said Dave Woodard, a political science professor at Clemson University in South Carolina. "He's conducted himself well, he's run a good campaign. He's been a decent candidate and decent candidates endorse the winner."
That endorsement could come in conjunction with Pennsylvania's April 24 primary. The expectation was that Santorum would stay in the race at least until his home state voted, but he was slipping in the polls.
Santorum lost his reelection bid to the U.S. Senate six years ago in Pennsylvania, something he didn't want to repeat, Woodard said. "They broke his heart once in 2006 and he sure didn't want to let them do it again."
Utah Republicans are looking forward to Romney being at the top of the ticket on the November ballot.
"Voter turnout in Utah will be at 105 percent," Chaffetz said. "We'll have people voting we didn’t' even know were alive. If you're a Democrat this year in Utah, wow. Good luck."
State Democratic Party Chairman Jim Dabakis tried to sound upbeat about his party's chances, but joked that with Santorum officially out of the race, "I've had to pull all those Santorum bumper stickers off my car."
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