Former Minnesota governor Tim Pawlenty plunged into the contest for the 2012 Republican presidential nomination Monday with a Facebook announcement in which he championed limited government and declared, “We the people of the United States will take back our government.”

Pawlenty, 50, stopped a step short of a formal declaration, which is likely to come later in the spring. But his decision to establish a presidential exploratory committee with the Federal Election Commission gives him the legal mechanisms to begin active fundraising and to build his campaign operation.

The long-anticipated announcement by Pawlenty signaled the acceleration of what has been a slow-starting race for the GOP nomination, with other prospective candidates expected to announce their intentions in the coming weeks.

Those likely candidates include former Massachusetts governor Mitt Romney, seen as a fragile frontrunner in the GOP sweepstakes; Mississippi Gov. Haley Barbour, who has been locking up talent and traveling to key states; and former House speaker Newt Gingrich, who has done everything to show he plans to run except form a presidential committee.

Considerable uncertainty surrounds the Republican race, considered to be as wide open as any in recent years. Among those still waiting to be heard from are former Arkansas governor Mike Huckabee, who won the Iowa caucuses in 2008; former Alaska governor and 2008 vice presidential nominee Sarah Palin; Indiana Gov. Mitch Daniels; and Rep. Michele Bachmann of Minnesota.

Pawlenty’s announcement came in a two-minute video replete with flags waving and a rich soundtrack. He spoke of his roots in a blue-collar suburb of the twin cities of Minneapolis and St. Paul to try to show that he understands the pain many families are still feeling as the economy slowly recovers from the collapse that began in late 2008.

His message was also aimed at tea party conservatives, one of the most energetic segments of the Republican Party. “This country was founded on freedom,” he said. “We the people of the United States will take back our government. This is our country. Our founding fathers created it. Americans embraced it. Ronald Reagan personified it, and Lincoln stood courageously to protect it. Together we’ll restore America.”

Pawlenty is little known nationally and registers in single digits in national polls testing the field of possible candidates. According to the most recent Washington Post-ABC News poll, nearly six in 10 Republicans said they didn’t know enough about him to offer an opinion.

But the former governor carries less obvious baggage than some of his better-known opponents. Aides said Monday that he will seek to portray himself as a bridge betweenthe fiscal and social conservatives within the party. And, aides said, Pawlenty has shown that his ability to appeal to independents would make him the strongest potential candidate against President Obama in the general election.

Alex Castellanos, a Republican strategist who is neutral in the GOP nomination battle, said Pawlenty’s attributes include an optimistic message that contrasts with the note of austerity coming from some congressional Republicans. “He has tapped a chord that is missing for Republicans in general,” Castellanos said.

But he added that it’s unclear whether Pawlenty can generate enough enthusiasm to win the nomination. “A lot of Republicans are concerned that he’s wet wood and won’t light. Is he as charismatic as his message?” Castellanos said.

Aides said Pawlenty intends to highlight his conservative record in a state best known for liberal politics. That record, they said, includes cutting state spending and taxes, vetoing tax hike measures, taking on public employee unions and instituting pension reforms for some public employees and health-care initiatives that contrast with Obama’s health-care law.

A spokeswoman for the Minnesota Democratic-Farmer-Labor-Party immediately attacked Pawlenty after the announcement. In a statement, Kristin Sosanie accused Pawlenty of leaving behind the largest deficit in the state’s history, higher property taxes and “draconian” cuts in education. “The last thing he deserves is a chance to do it to our nation,” she said.

Pawlenty will begin his campaign strategy by turning to neighboring Iowa. A victory in those caucuses early next year could be a springboard to boost his profile. And it could provide the momentum to compete effectively in New Hampshire, where Romney is the clear favorite, and elsewhere. A poor finish in Iowa, however, could cripple his candidacy.

Pawlenty aides said that in using Facebook to make the announcement, the former governor showed that he’ll make the maximum possible use of new technology and social networking in his campaign.

Four years ago, a number of candidates announced their intentions to run for office by posting videos on their campaign committee Web sites. Obama’s campaign went on to exploit technology more effectively than anyone had done previously. Pawlenty’s use of Facebook shows the rapidly evolving role of social networking in all facets of politics and likely will become standard in all 2012 campaigns.