WASHINGTON - President Barack Obama kicked off a three-day campaign-style bus tour Monday with a rare direct attack against the newly emboldened Republican presidential field, criticizing his potential 2012 rivals for their blanket opposition to any deficit-cutting compromise involving new taxes.
Republicans, meanwhile, grappled for the spotlight as the top tier of candidates began to take shape.
Obama's tour comes after the president spent much of the summer holed up in Washington enmeshed in bitter, partisan negotiations on the U.S. debt crisis that cratered his approval ratings and those of Congress amid a faltering economy and high unemployment.
Obama recalled a moment in last week's Republican presidential debate when all eight of the candidates said they would refuse to support any deal with tax increases, even if tax revenues were outweighed 10-to-1 by spending cuts.
"That's just not common sense," Obama told the crowd at a town hall-style meeting in Minnesota, as he launched a tour through the Midwest.
"You need to take a balanced approach," he insisted.
Obama didn't mention any of the candidates by name, and prefaced the remark by saying, "I know it's not election season yet."
But his comment underscored that election season is indeed under way. The bus tour, although an official White House event rather than a campaign swing, also takes Obama through Iowa and Illinois, all states he won in 2008 but where he now needs to shore up his standing.
It gives him a chance to return to the grassroots campaigning that helped propel him to the White House, and he shed his jacket and tie to mix it up with voters in coffee shops and lunch joints far from Washington.
In Iowa, Obama returns to a state that handed him a key victory over Democratic rival Hillary Rodham Clinton in their nomination fight but where Republicans have now been blanketing the state in preparation for its first-in-the-nation caucuses, attacking the president at every turn. The bus tour comes on the heels of Congresswoman Michele Bachmann's weekend victory in an influential poll and Texas Gov. Rick Perry's contest-rattling entrance into the race.
Later in the town-hall meeting, Obama got a question on his signature health care reform law, and took a hard shot at Mitt Romney, a Republican front-runner who has had to defend implementing a health care plan while governor of Massachusetts that's similar to the federal version.
"You've got a governor who's running for president right now who instituted the exact same thing in Massachusetts," Obama said, referring to a central component of his law -- the requirement for nearly everyone to carry health insurance.
"This used to be a Republican idea," Obama said.
Romney, who has been riding high for months while other Republicans have been struggling to emerge from the pack, now finds himself facing two significant foes in Perry and Bachmann.
Romney declared on Monday his business background sets him apart in the presidential race and dismissed the buzz over emerging challengers as "the political winds of the day." Perry insisted no one could go "toe to toe" with him.
In less than a week, the slow-to-begin race for the Republican nomination has accelerated and undergone a dramatic shift, essentially becoming a three-way contest for the chance to challenge Obama next year.
Romney, who lost the nomination in 2008, hasn't been able to unite warring factions of the Republican electorate since entering the race earlier this year. Social conservatives and the tea party movement haven't warmed to his candidacy, and he has left some economic conservatives and Republicans in the party establishment underwhelmed.
Bachmann and Perry both have support among the tea party and Christian evangelicals, and both are competing hard in Iowa, where social conservatives dominate.
Romney provided a window into how he would address Perry's entry into the race.
"Understanding how the economy works by having worked in the real economy is finally essential in the White House. And I hope people recognize that," Romney said, stressing his years of private business experience and drawing a contrast with Perry, Texas' longest-serving governor who never has worked in the private sector as an adult.