WASHINGTON - One year after President Barack Obama signed his historic health care overhaul, the law is taking root in the land. Whether it bears lasting fruit is still in question.

The legislation established health insurance as a right and a responsibility. Thousands of families, businesses and seniors have benefited from its early provisions.

But worries about affordability and complexity point to problems ahead. And that's assuming it withstands a make-or-break challenge to its constitutionality that the Supreme Court is expected to decide.

Public divisions over the law are still so sharp that Americans can't even agree what to call it. Supporters call it the Affordable Care Act, a shorter form of its unwieldy official title. It's also known as "Obamacare," the epithet used by Republicans seeking its demise.

While Obama returns from Latin America on the signing anniversary Wednesday, administration officials will fan out across the country. Community commemorations started Monday, underscoring that the health care battle has moved to the states. Even states suing to nullify the law's requirement that most Americans carry health insurance are proceeding with at least some of the building blocks.

Polls show that about one in eight people believe they have been personally helped already, well before the provision kicks in 2014 to cover millions of uninsured. Interviews with people affected reveal it's not always clear-cut.

In small-town Circleville, N.Y., Patti Schley says one of the dozens of new insurance regulations made a dramatic difference for her family.

Her daughter Megan, 23, was out of college, going without insurance as she tried to launch a wedding photography business. Last summer Megan started getting sick and rapidly lost weight. Doctors diagnosed a serious digestive system disorder that would make her uninsurable.

But her parents were able to get her into a high-risk insurance pool created under the law, and this year Megan signed up for her father's workplace plan, under a provision extending coverage for adult children up to age 26.

"As a mother of a sick child, you are concerned whether your kid is 4 or 24," said Schley, an office administrator. "We couldn't wait for this to kick in."

Things are working out for the Schleys, but the high-risk pools that provided the initial lifeline for Megan are faltering. Nationally, the latest count shows fewer than 12,500 people signed up, mainly because of waiting periods and high premiums.

Another mom with an uninsured daughter ran into a Catch-22 that illustrates the law's complexity.

Mary Thompson of Overland Park, Kan., was sure the law would finally get 11-year-old Emily on the family's health insurance.

Insurers had repeatedly rejected Emily due to a birth defect of the spine, surgically corrected when she was an infant. The law requires insurers to accept children regardless of pre-existing health problems, a safeguard that will extend to people of all ages in 2014.

But because Emily's father is self-employed and the family buys its own coverage, things didn't work out as expected.

Certain "grandfathered" plans selling individual coverage are exempt from the law's requirement to cover kids. The Thompsons' plan was one. That meant they would have to apply for a whole new policy, and the mother, a breast cancer survivor, was unlikely to be accepted.

"We would have had to start over with me - and I can't start over," said Thompson. A social worker helped get Emily into Medicaid.

In neighboring Missouri, an insurance company's campaign to get small businesses to sign up by taking advantage of new tax breaks has yielded mixed results.

One of the chief promoters of the idea is Ron Rowe, an executive of Blue Cross and Blue Shield of Kansas City. With some 150 previously uninsured businesses offering new coverage, his company's efforts earned the praise of Obama administration officials. But Rowe says many business owners found the math didn't work for them.

"The longer this has been out in the marketplace, the less appealing it's been to small-business owners," he said. A typical employee with 10 workers would have to pay about $31,000 a year for health insurance and recover only 10 percent to 15 percent of that through the new tax credit.

Rowe says his company is getting more interest from business owners by offering a cap on rate increases.

No group is more sensitive to medical costs than senior citizens, whose votes are also critical to Democrats' chances in the 2012 presidential election. So far, alarms that Medicare cuts would compromise their care have not been borne out. But Democratic lawmakers engineered the cuts to take effect gradually, while new Medicare benefits are being provided now.

Topping the list this year is a 50 percent price cut on brand-name prescriptions for Medicare recipients who fall into the coverage gap called the "doughnut hole." Daniel Wisniewski, a retired truck driver from Staten Island, N.Y., reckons that will reduce the price of one of his heart drugs from $234.99 a month to around $117.

"I'm not much on politics, but I feel that that's got to help me," said Wisniewski, 69. "I worked and paid into Social Security for 55 years. When I was a kid I used to wash dishes in a bakery after school."

Republicans say such gains will be temporary. For families, "any marginal benefits from this law are far outweighed by the heavy-handed intervention in their health care by Washington bureaucrats," said Sen. Orrin Hatch, R-Utah.

Affordability is the main worry for critics. A recent poll by the nonpartisan Kaiser Family Foundation found that one in five Americans said they had been negatively affected by the law, and about half of those cited costs. Some blamed the law for this year's premium hikes, although many experts say the impact was marginal.

"If they have a bad experience in the marketplace, it's very possible they're going to attribute that to the law," said Mollyann Brodie, Kaiser polling director. "It certainly presents a challenge for the proponents."

A lead author of the bill, Democratic Sen. Max Baucus of Montana, remains a strong supporter but laments not devoting more attention up front to cost control. "It gave detractors an opening," he said.