Gov. Tim Pawlenty is raising the prospect of blocking national health care reform in Minnesota by possibly invoking the U.S. Constitution's 10th Amendment on states' rights.

Defense of states' rights has long been a rallying cry for critics of federal power, and Pawlenty's remarks echo those of other Republicans who are considering using constitutional muscle to oppose President Obama's proposals to overhaul the nation's health care system.

During a conference call Thursday night with reporters and conservative activists, Pawlenty said that "asserting the 10th Amendment" of the U.S. Constitution might allow Minnesota to sidestep federally imposed changes to the health care system.

"Depending on what the federal government comes out with here, asserting the 10th Amendment may be a viable option but we don't know the details," Pawlenty said in a recorded response to a question that was posted online by Minnesota Public Radio.

Pawlenty returned to the topic on Friday during his weekly radio show, posing an assertion of states' rights as a counterweight to "a federal government that permeates every aspect of our lives. ... [We should] at least have a discussion," he said, "not talking about seceding from the union and not filing lawsuits."

But during his Thursday call, Pawlenty had said that there could be lawsuits.

The 10th Amendment states that powers "not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States."

State DFLers pounced quickly on the comments.

"Governor Pawlenty continues his political posturing on health care to the detriment of Minnesotans," said Rep. Paul Thissen, DFL-Minneapolis, a gubernatorial candidate who leads the House Health and Human Services Policy Committee.

"The 10th Amendment has often been asserted by states as a reason to resist the imposition of federal policy," said University of Minnesota law professor Dale Carpenter, an expert on constitutional law. "But that resistance has not often been successful in litigation."

The federal government has asserted power over health insurance since the New Deal in the 1930s, he said. "The governor might disagree with that interpretation ... but it is unlikely that courts are going to reverse more than 70 years of precedent of expanding federal power."

"My guess is that the governor is employing this more as a rhetorical and political argument than as a legal or constitutional argument," he said.

Indeed, by Friday, Pawlenty's remarks were being chewed over by TV pundits and had landed him on top of political websites, furthering his exposure.

Building on Pawlenty's comments, House Republicans Tom Emmer, Mark Buesgens and Peggy Scott announced that they would propose a state constitutional amendment "protecting health care freedom of choice."

Next year, Arizona residents will vote on a state constitutional amendment that would let them effectively opt out of any proposed national health care plan, according to the Tenth Amendment Center, which supports the assertion of states' rights. Sarah Palin, when she was Alaska's governor, and Texas Gov. Rick Perry backed resolutions affirming their states' sovereignty under the 10th Amendment.

While the defense of state's rights usually is championed by conservatives, it sometimes has been used by others opposed to federal legislation, said Michael Boldin, founder of the Tenth Amendment Center. He noted that liberals have raised 10th Amendment arguments in opposition to federal restrictions against medical marijuana.