DENVER – President Obama’s legacy just might be in the hands of people such as Matt Wright.

The 31-year-old real estate agent worries less about his lack of health insurance coverage than he does about the costs of buying it when the Affordable Care Act mandates kick in, on top of all the expenses of providing for his 4-year-old daughter. “I have an open mind with a bunch of ‘if’s,’” he says.

In Colorado and across the country, the insurance marketplaces known as exchanges are scheduled to open Tuesday, and the success or failure of Obama’s signature legislative achievement is at stake. Passing the health-care overhaul defined much of his first term in the White House, and defending it from Republican assault has defined much of his second – including in the current budget showdown.

Americans who don’t have insurance, or who have been buying individual policies, or who work for some small businesses, are urged to go online to shop for plans and to determine if they’re eligible for federal tax credits to help cover the cost. Whether the system is easy to navigate and the plans judged a good value are likely to set attitudes toward a law that at the moment remains unpopular – shaping Obama’s legacy.

USA TODAY decided to explore the issue in Colorado, one of the nation’s most critical swing states and the place where Barack Obama was nominated for president in 2008 with a pledge to overhaul the nation’s health-care system. The news organization sponsored a statewide poll this month and convened a focus group of 10 Denver-area residents who don’t have health insurance.

What USA TODAY found underscored the uphill battle for “Obamacare” three years after it was signed into law. Confusion about the law is widespread, including among those who are supposed to benefit from it, and opposition as fierce as ever.

By 52 to 33 percent, Colorado residents disapprove of the Affordable Care Act. More than two-thirds say they don’t understand it very well, and a majority predict the overall effect of the law on the country in coming years is going to be mostly negative.

Among those who disapprove of the law, an overwhelming majority (54 percent to 37 percent) want elected officials who agree with them to do what they can to make the law fail. Even though Democratic Gov. John Hickenlooper and the Colorado Legislature back key provisions – expanding Medicaid eligibility and establishing a state exchange – approval of the law is lower in Colorado than nationwide, and the opposition is more fervent.

During a roundtable discussion that stretched nearly two hours, the uninsured who are intended to benefit from the law expressed skepticism and confusion about it. Not one understands how to shop for a plan, and some hadn’t realized that the law requires them to get coverage next year or pay a fine.

Asked to describe Obamacare in a word or phrase, Robert Widgery said, “Government boondoggle.” Catherine Campbell: “Worried I can’t afford it.” Elizabeth Espinosa: “I don’t know what it is.”

Neil Carr offered, “Not perfect but on the right track” and Mary Anne Torongo says simply, “A relief.”

When Torongo, 57, the mother of two grown children, sliced her thumb recently, she called a friend who is a nurse instead of going to an emergency room. The friend used superglue to close the wound. “I didn’t even ski last year because I don’t have insurance,” Torongo says, for fear of taking a bad fall. “I don’t want to have to limit myself in living my life because I don’t have health insurance.”

She works as an aesthetician, giving beauty treatments and her employer doesn’t offer health insurance. “Once this Obamacare comes into play, we will be able to have our coverage this time,” she says. She and her co-workers “are very happy.”

Wright is still trying to figure out how it will work for him. “I think I have the idea behind it, probably comparable to car insurance, where we have to have it, so do I go with Allstate? Do I go with Progressive?” he says. “I’m hoping that the competitive environment of a marketplace would have prices become more reasonable, with multiple options.” But he said, “At this point, it’s to be determined, right?”

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