NEW ORLEANS - President Barack Obama and Republican Sarah Palin sparred from a distance over nuclear policy with each questioning the other's experience on the issue in a potential preview of the 2012 White House race. "Unbelievable," Palin said earlier this week after Obama rewrote the U.S. nuclear strategy, and she suggested the president was weak on nuclear defense.

NEW ORLEANS - President Barack Obama and Republican Sarah Palin sparred from a distance over nuclear policy with each questioning the other's experience on the issue in a potential preview of the 2012 White House race.

"Unbelievable," Palin said earlier this week after Obama rewrote the U.S. nuclear strategy, and she suggested the president was weak on nuclear defense.

Obama, in Prague to sign a nuclear reduction treaty with Russia, countered by deriding the former Alaska governor who resigned midway through her first term as "not much of an expert" on nuclear issues.

Palin then shot back Friday during a speech to the Southern Republican Leadership Conference in New Orleans with a reference to Obama's early career choice. Mocking the president, she dismissed "all the vast nuclear experience that he acquired as a community organizer."

Playing out over several days and across the globe, the spat foreshadowed what the country could see come the next presidential race should Palin run for president and win the GOP nomination.

The 2008 vice presidential nominee is among roughly a dozen Republicans weighing candidacies. It's a wide-open field but Republican insiders say Palin would be a serious contender if she got in the race. She is beloved by tea party activists. She's a political celebrity who draws tons of media coverage. And she has an ability to raise big money. But she's also polarizing, and there's no evidence that she can broaden her base of support beyond conservatives to win the GOP nomination, much less to beat a popular Democratic president.

Nevertheless, Palin is leaving the door open to a candidacy and has spent the past few months pummeling Obama in speeches, interviews and online. She used her speech in New Orleans to blister the president repeatedly, as did several of her potential rivals who also spoke at the three-day event.

But Obama rarely if ever responds directly to Palin. The president typically doesn't counter criticism from Republicans weighing whether to challenge him. Doing so always has the potential to elevate a rival.

The spat began Wednesday when Palin criticized Obama's rewriting of the U.S. nuclear defense policy. Her comments came during an interview on Fox News, where she is a paid analyst. Palin was particularly incensed about the policy that says if a non-nuclear state were to use chemical or biological weapons against the U.S. or its allies, it would face a potentially devastating conventional military strike by the U.S., but not a nuclear one.

"No administration in America's history would, I think, ever have considered such a step that we just found out President Obama is supporting today," Palin said.

Across the globe in Prague, Obama was asked by ABC News to respond to the criticism.

"I really have no response," the president said. "Because last I checked, Sarah Palin's not much of an expert on nuclear issues."

Obama added: "If the secretary of Defense and the chairman of the Joint Chiefs of Staff are comfortable with it, I'm probably going to take my advice from them and not from Sarah Palin."

Palin got what could be the last word in her Friday speech in New Orleans. Among several potential candidates addressing the GOP rank and file at the conference, Palin got a rousing reception from the few thousand activists in attendance and delivered a speech rife with platitudes for the GOP and criticism for Democrats.

Some in the crowd responded with a "Run, Sarah, run" chant. She didn't say whether she would.

But Louisiana Gov. Bobby Jindal made his plans clear, telling the audience: "I am not running for president of the United States of America. I've got the job that I want."

Texas Gov. Rick Perry of Texas also spoke Friday. He did not tip his hand about 2012, but had this to say about November's congressional elections: "It's going to take men and women going to Washington, D.C., and saying no." He said GOP candidates should tell voters, "Elect me and I'm going to Washington, D.C, and will try to make it as inconsequential on your life as I can make it."

On Thursday, Newt Gingrich called Obama "the most radical president in American history." On tap for Saturday: Indiana Rep. Mike Pence, former Pennsylvania Sen. Rick Santorum, Mississippi Gov. Haley Barbour and Texas Rep. Ron Paul.

At least four possible candidates passed up the event.

Minnesota Gov. Tim Pawlenty was addressing the activists by video so he could welcome home returning troops. Former Arkansas Gov. Mike Huckabee and South Dakota Sen. John Thune also were absent.

Former Massachusetts Gov. Mitt Romney was in the midst of a book tour and he spoke late Friday in Bloomington, Minn. He criticized the nuclear reduction treaty as one that will "weaken America and weaken our capacity to protect ourselves."