March 23, 2010: Obama signs the Patient Protection and Affordable Care Act (ACA). Democrats hail an achievement their party pursued for more than 50 years — individuals' right to health care.

Fall 2010: During open enrollment, most health insurance plans begin offering coverage to people as old as 26 on a parent's policy. It expanded coverage to more than 3 million people. Plans also begin covering preventive services.

Nov. 2, 2010: Democrats lose control of the House in midterm congressional elections. Republicans campaigned on a vow to "repeal and replace" the law.

Jan. 19, 2011: The Republican-led House votes to repeal the law, but the drive falters in the Senate.

Jan. 31, 2011: Florida U.S. District Judge Roger Vinson rules that the law is unconstitutional.

April 5, 2011: Congress votes to repeal an unpopular tax requirement in the law that would have forced millions of businesses to file tax forms for every vendor selling them more than $600 in goods.

June 21, 2011: The Obama administration says it will fix glitch that would have let several million middle-class people get nearly free insurance meant for the poor. The fix saves about $13 billion over 10 years.

Summer 2011: Seniors hitting Medicare's prescription drug coverage gap start getting a 50 percent discount on brand name medications. In 2011, the typical senior in the gap saved $600 on bills averaging $1,500.

Aug. 1, 2011: Sebelius says most plans will have to cover birth control for women, free of charge. Available in 2013.

June 28, 2012: With the unlikely support of conservative Chief Justice John Roberts, the high court upholds the law's core requirement that most Americans carry health insurance, ruling that the penalties to enforce it are a tax Congress is authorized to levy. But it allows states to opt out of the Medicaid expansion.

Oct. 1: Online insurance markets to open. Consumers must sign up by Dec. 15 for Jan. 1 coverage.

Associated Press

LOCATION MAY MATTER

Having health insurance used to hinge on where you worked and what your medical history said. Soon that won't matter, with open-access markets for subsidized coverage coming Oct. 1 under President Obama's overhaul. But there's a new wild card, something that didn't seem so critical when Congress passed the law in 2010: where you live.

Entrenched political divisions over "Obamacare" have driven most Republican-led states to turn their backs on the biggest expansion of the social safety net in a half-century. If you're uninsured in a state that's opposed, you may not get much help picking the right private health plan for your budget and your family's needs.

The differences will be more glaring if you're poor and your state rejected the law's Medicaid expansion. Unless leaders reverse course, odds are you'll remain uninsured. That's because people below the poverty line do not qualify for subsidies to buy coverage in the markets. "We are going to have a new environment where consumers may be victims of geography," said Sam Karp of the California HealthCare Foundation, a nonprofit. "If I'm a low-wage earner in California, I may qualify for Medicaid. With the exact same income in Texas, I may not qualify."

The health care law is finally leaving the drawing boards to become a real program. In many parts of the country, the decisions of Republicans opposed to the law will trump the plans of Democrats who wrote it. Still, there is a new bottom line. Health insurance marketplaces in every state will provide options for millions who don't have job-based coverage, who can't afford their own plan or have a health problem that would get them turned down. The feds will run the markets in states that refused to do so. The coverage won't be free, even after sliding-scale subsidies keyed to your income.

ASSOCIATED PRESS