Romney heaped praise on his 2012 running mate, Wisconsin Rep. Paul Ryan, while naming a handful of governors who have sought a larger national profile, including Bob McDonnell of Virginia and Chris Christie of New Jersey.
Neither Christie nor McDonnell were invited to the conference after rankling conservatives in recent months for, among other things, supporting efforts to expand Medicaid coverage as part of Obama's health care overhaul.
Most of the candidates have been working to raise their national profiles while tiptoeing around questions about their presidential ambitions.
Walker told The Associated Press late last month that a 2016 presidential bid "would be an option," although it wasn't something he was "actively pursuing."
Paul has said he's "seriously considering" running for the White House. Ryan, the House Budget Committee chairman, has avoided such questions and instead continued his central role in one of Capitol Hill's most significant policy debates.
Jindal laughed off questions about his future: "Any Republican that's thinking about talking about running for president in 2016 needs to get his head examined," he said last month. "We've got a lot of work to do."
And of course there is an even fresher crop of conservatives auditioning as well.
Ben Carson, a neurosurgeon who was critical of Obama's policies during the National Prayer Breakfast, told activists Saturday that he would soon retire from medicine and could have a future in politics.
"Let's say you magically put me in the White House," Carson said before being interrupted by cheers.
"Who knows what I'm going to do," he said.
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