Rick Santorum announced Tuesday that he is suspending his presidential campaign, leaving Mitt Romney to wrap up the Republican nomination to take on President Obama despite still having GOP hopefuls Newt Gingrich and Ron Paul in the race.

AEI scholars say let the general election begin.

"Rick Santorum’s decision to suspend his campaign confirms that the GOP race is over. Romney has already pivoted to Barack Obama.  Campaign on," said AEI Senior Fellow Karlyn Bowman, an expert on American voting and public opinion trends. "How long it will take campaign wounds to heal remains to be seen.  Romney needs to reach out to Santorum supporters while zeroing in on Barack Obama."

But even with Santorum out, his role in the GOP is not over.

"Can Rick Santorum come back after some surprising successes in the 2012 race?  He’s young and has a strong base of supporters.  While the 2012 race is over for him, he is, as he said, not finished yet," Bowman said.

"Every time he went to a state, even if he didn't win, he built up a network," countered Henry Olsen, vice president of the American Enterprise Institute, in remarks to NPR. "Why should he have cut that short to curry favor with the big-money people lined up behind Romney, who aren't going to like him in four years anyway?" 

In an AEI analysis of polling data earlier this year, it was shown that Santorum may be the conservative choice for many Republican voters, but it's a myth to think Romney can't win them over. In one-on-one matchups taken at the time by Economist/YouGov, self-identified conservatives backed Romney over the two leading conservative alternatives: Gingrich and Santorum.

Click here to read AEI's Special Topics section on the 2012 election.