WASHINGTON - Hosting a gathering of young conservatives at a bar here this month, former Minnesota Gov. Tim Pawlenty delivered a tart critique of the nation's mounting debt. He called it a "pile of poo."

Elsewhere in public, especially before key conservative groups, Pawlenty has termed federal spending a "Ponzi scheme" and President Obama as someone who has "proven that someone can deserve a Nobel Prize less than Al Gore."

Still amiable but increasingly sharp-tongued, Pawlenty has shown he can serve up the meat and potatoes the GOP's Tea Party base craves. But for some in the GOP's mainstream establishment, the ramped-up rhetoric could test his viability as a presidential hopeful in 2012.

Polling nationally in the single digits, Pawlenty is trying to break out with strongly worded stands on deficit spending and national defense. On national TV, he has accused Obama of being "nearly incoherent" on the Egyptian uprising. At a conference of conservative activists, he said Obama was too ready to "appease" Iran, Russia and the Muslim Brotherhood.

While he said he would not question Obama's birth certificate, he did ask conservatives at a recent gathering, "Don't you at least wonder what planet he's from?"

Pawlenty had been typecast by national political watchers as the mild Midwesterner, a polite conservative who stayed away from rough stuff. So what happened to Mr. Nice Guy?

Pawlenty watchers say his basic conservatism hasn't changed, only his willingness to let fly the flourishes necessary to grab attention in a crowd of GOP presidential contenders.

"We know everybody is edging up to the starting line," said former state legislator Phil Krinkie, president of the Minnesota Taxpayers League. "And, yeah, it's time for him to be a little more bold, a little more aggressive, ramping it up."

To businessman Brian Sullivan, who ran to the right of Pawlenty for the 2002 GOP nomination for governor, Pawlenty is hitting all the right notes. "Tim has done a very good job of establishing himself as a top-tier candidate who's got as good a shot as anybody," he said.

Brian Jencunas, a Massachusetts college student at this month's Conservative Political Action Conference, praised Pawlenty's hard-nosed fiscal record. "He's not one of the pretty people," he said. "He's not one of the screamers."

The former governor's campaign to raise his national profile includes a book ("Courage to Stand") and a video that traffics less in dry policy specifics than in apocalyptic calls for fiscal discipline -- the core of his case for the presidency. The video, which some have likened to an action-hero movie trailer, contains the stump speech line, "Valley Forge wasn't easy."

Some of the party's intellectual Brahmins think Pawlenty is running beneath himself. "Pawlenty was a successful two-term governor," wrote David Frum, a former speechwriter for President George W. Bush. "Yet, in sharp contrast to fellow Midwesterner Mitch Daniels, Pawlenty is running a campaign of gimmicks and slogans."

'Too transparent'

Bruce Bartlett, once an adviser to Ronald Reagan, is even tougher on Pawlenty. Bartlett seized on Pawlenty's opposition to a higher national debt ceiling, a view that positions him to the right of GOP leaders like House Speaker John Boehner of Ohio.

Taking aim at Pawlenty's alternative proposal for a balanced budget amendment to the U.S. Constitution, which would take years, Bartlett wrote that Pawlenty is "not ready for prime time."

"He may think he has found a clever way of appealing to the right wing Tea Party/Fox News crowd without having to propose any actual cuts in spending, but it's not going to work," Bartlett said. "It's too transparent and phony even for them."

Pawlenty backer Ron Eibensteiner, former Minnesota GOP chair, notes that Reagan, too, backed a balanced budget amendment. Even if it's not politically viable, Eibensteiner said, "it's worth putting in front of the American people to get their attention."

Even if it doesn't please some of the party highbrows, political insiders say Pawlenty has little choice but to reach out to the conservative voter base, which he has done by invoking his evangelical faith.

Pawlenty will make his case this weekend to the Tea Party Patriots' first summit in Phoenix.

"He's a more articulate Michele Bachmann," said former U.S. Sen. David Durenberger, a Minnesota Republican. "And appropriately so, if the chance that he has is to be the Republican nominee for president. I don't know another way you go about it other than the one he has chosen."

For other old-time Republicans, Pawlenty's rhetorical arc has tracked the party's ideological trajectory to the right.

Former Republican Gov. Arne Carlson said a big part of Pawlenty's once-moderate image stemmed from his 1993 vote to include gays and lesbians in the state's Human Rights Act. Pawlenty was one of only 11 Minnesota House Republicans to do so, and he later came to regret it. He now opposes letting gays serve openly in the military.

Carlson also said he "can't find a difference" between federal deficit spending and the $6.2 billion projected state deficit Pawlenty left behind.

Pawlenty backers blame DFL legislators.

Power Line blogger John Hinderaker of Apple Valley said Pawlenty has a solid conservative record.

"I don't see any evidence that he has changed the substance of his positions," he said. "Stylistically, I think he has come across lately as stronger and more presidential. That's a good thing, if he wants to put his hat in the presidential ring."

Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.