ST. PAUL — In more than a dozen statehouses across the country, a small but growing group of lawmakers is pressing for state constitutional amendments that would outlaw a crucial element of the health care plans under discussion in Washington: the requirement that nearly everyone buy insurance or pay a penalty.

Approval of the measures, the lawmakers suggest, would set off a legal battle over the rights of states versus the reach of federal power — an issue that is, for some, central to the current health care debate but also one that has tentacles stretching into many other matters, including education and drug policy.

Opponents of the measures and some constitutional scholars say the proposals are mostly symbolic, intended to send a message of political protest, and have little chance of succeeding in court over the long run. But they acknowledge that the measures could create legal collisions that would be both expensive and cause delays to health care changes, and could be a rallying point for opponents in the increasingly tense debate.

“This does head us for a legal showdown,” said Christie Herrera, an official at the American Legislative Exchange Council, a group in Washington that advocates limited government and free markets, and that earlier this month offered guidance to lawmakers in more than a dozen states in a conference call on the state amendments.

So far, the notion has been presented in at least 10 states (though it has already been rejected or left behind in committees in some of them), and lawmakers in four other states have said they will soon offer similar measures in what has grown into a coordinated effort at resistance. (Arizona, which has placed the amendment on its ballot in 2010, seems the furthest along.)

Here in Minnesota, as in many of the other states, the move to amend the State Constitution is being driven by a handful of Republican lawmakers. The proposed amendment itself does not advocate some particular alternative plan, but sets what its authors see as ground rules for what any future health care system should — and should not — include.

“All I’m trying to do is protect the individual’s right to make health care decisions,” said State Representative Tom Emmer, a Republican. “I just don’t want the government getting between my decisions with my doctors.”

Many who favor a federal overhaul of health care say it can be affordable only if nearly everyone is required to carry insurance, but the efforts by these state lawmakers actually predate the Obama administration and the current federal health care debate.

Proposed constitutional amendments began cropping up after 2006, when Massachusetts enacted a sweeping state measure meant to create nearly universal health coverage for residents. Elsewhere, some leaders — opposed to the possibility of insurance mandates or government-run systems — began suggesting constitutional amendments to block such measures from their own states.

In Arizona, with help from Dr. Eric Novack — an orthopedic surgeon who says his intent was not “some grand secessionist plot” but merely a health care overhaul with protections for individuals’ rights — an amendment first went before voters in 2008. It was defeated, but by fewer than 9,000 votes among more than two million cast.

This year, Arizona’s Legislature, controlled by Republicans in both chambers, voted to put the question back on the ballot in 2010.

Few in the public seemed focused on health care a year ago, those involved in Arizona’s ballot question said, but the recent debate over a federal overhaul has changed all that, and proponents of the amendment believe that will improve its chances both in Arizona and in other states, where similar efforts have taken root.

The federal proposals, though, have also changed the potential fallout if such amendments were to pass.

Clint Bolick, litigation director at the Goldwater Institute, a conservative research group based in Arizona that favors free enterprise, and who has helped lead Arizona’s efforts, said he believed the inevitable “legal clash” — if the federal government adopts a health care law and if states change their constitutions — was winnable for the states.

Although the United States Constitution’s supremacy clause ordinarily allows federal law to, in essence, trump a state law that conflicts with it, Mr. Bolick said that was not always the case, depending on “the strength of the state interest.” Mr. Bolick said he viewed two recent Supreme Court cases, related to an education question in Arizona and a utility district in Texas as indications that the current court might be open to such a state claim.

But several other legal experts said they saw little room for such a challenge. “States can no more nullify a federal law like this than they could nullify the civil rights laws by adopting constitutional amendments,” said Timothy Stoltzfus Jost, a health law expert at Washington & Lee University School of Law.

Mark A. Hall, a law professor at Wake Forest University who has studied the constitutionality of mandates that people buy health insurance, said, “There is no way this challenge will succeed in court,” adding that the state measures seemed more “sort of an act of defiance, a form of civil disobedience if you will.”

Even Randy E. Barnett, a Georgetown law school professor who has written about what he views as legitimate constitutional questions about health insurance mandates, seemed doubtful.

“While using federal power to force individuals to buy private insurance raises serious constitutional questions,” Professor Barnett said, “I just don’t see what these state resolutions add to the constitutional objections to this expansion of federal power.”

In Minnesota, even before the prospect of a court clash, Mr. Emmer appears to have an uphill battle ahead. Before voters can consider amending the state’s Constitution, Mr. Emmer needs approval from the Legislature, which is dominated by Democrats. He has offered the Health Care Freedom Act in years past, but it has never made its way to a vote, and Margaret Anderson Kelliher, a Democrat and speaker of the House who is also among the wide field of candidates for governor, said last week that she doubted it stood much of a chance this time either.

“Most legislators are interested in improving the health of Minnesotans, and how to do more health care reform,” Ms. Kelliher said. “No one thinks the answer is a states’ right movement.”

Still, Mr. Emmer, who is a candidate for governor, says he is hopeful. He emphasizes that such an amendment — regardless of court battles over a federal plan — would certainly spare Minnesotans from the potential downsides of some future state health care plan.

And this whole amendment notion, he said, would not prevent anyone from taking part in a federal health program; it would merely block people from being forced to do so.

As for legal experts’ discounting the states’ chances of trumping a federal plan, Mr. Emmer seemed unconvinced.

“They’re essentially saying that state constitutions are meaningless,” he said, “and I disagree.

“And tell me where in the U.S. Constitution it says the federal government has the right to provide health care? This is the essence of the debate.”