WASHINGTON — Minnesota Gov. Tim Pawlenty and Indiana Rep. Mike Pence, two possible 2012 presidential candidates, called for a return to conservative principles before a critical constituency Friday, while Mississippi Gov. Haley Barbour wouldn't rule out a White House bid of his own.

"If you see me losing 40 pounds that means I'm either running or have cancer," quipped Barbour, a former lobbyist and GOP chairman who Republican insiders say could be a formidable candidate.

The head of the Republican Governors' Association, Barbour made the comments to a group of reporters ahead of a weekend meeting of the nation's governors. He said he would focus this year on helping Republicans elected in governor's races. After November, Barbour said, he might considering running. Still, he called the prospect unlikely.

Several Republicans considering running for president were descending on Washington this weekend for the Conservative Political Action Conference and the National Governor's Association meeting, where they were testing the 2012 ground — even if they wouldn't acknowledge it.

Earlier Friday across town, Pawlenty and Pence were the latest Republicans weighing candidacies to speak to the annual gathering of thousands of conservative activists and leaders who are important players in the GOP base. Barbour made an impromptu stop at the event late Friday. Former Pennsylvania Sen. Rick Santorum and former House Speaker Newt Gingrich were on tap to deliver speeches Saturday.

Former Massachusetts Gov. Mitt Romney, who lost his 2008 Republican primary bid, made a splash at the conference Thursday. He's considered among the strongest prospective candidates, given that he has the experience of running before.

Romney, who brought along his state's new Republican senator Scott Brown to introduce him, delivered an impassioned defense of conservatism and indictment of President Barack Obama's first year to a cheering and chanting crowd. It was standing-room only for his mid-afternoon speech. His would-be campaign staff was on hand.

The reception for Pawlenty's midmorning speech a day later was more muted. He received a standing ovation and polite applause. The ballroom was just partially filled; there were empty seats throughout, though that could have been because of the hour. He, too, had aides nearby who are helping him lay the groundwork for a possible run.

Pawlenty sought to draw a stylistic contrast with Romney, who spoke from prepared remarks on a teleprompter. Aides said Pawlenty spoke more extemporaneously, drawing from bullet points written in a notebook on the lectern. His speech was part conservative pep talk, part criticism of Obama.

He laid out a vision of smaller government and a strong defense. The other principle he said guides him: "God's in charge."

"If it's good enough for the Founding Fathers it should be good enough for each and every one of us," said Pawlenty, noting that God is enshrined in the country's founding documents.

Pawlenty, who is not known for wearing religion on his sleeve, noted that some people said it would be "politically incorrect" to bring up God. "Hogwash," Pawlenty said, drawing applause from a crowd that clearly appreciated his pitch.

He belittled Obama as a president of "hope and change and teleprompters." He also said: "If government spending were an Olympic sport, he would be a repeat gold medalist." And he said: "Mr. President, no more apology tours and no more giving Miranda rights to terrorists in our country."

In contrast to Pawlenty, Pence delivered a robust speech that this partisan crowd ate up. It was filled with criticism of Obama and lines tailor-made for the GOP's right wing, including a pitch to "defend life."

"Conservative Republicans are back and we're in the fight for fiscal discipline. We're on the side of the American people," he declared.

Pence, too, took Obama to task, earning thundering applause throughout.

"The job of the American president is not to manage American decline. The job of the American president is to reverse it," Pence said, nearly yelling. "Get government out of control, get government out of the way and America will come roaring back!"