The Medicaid expansion is one of several health care changes set to take effect next year, including the law's most high-profile elements, including the ban on dropping patients with pre-existing conditions, ban on annual benefit limits and the health insurance exchanges. About half of the states have said they will conduct their own exchanges; exchanges in the other states will be run by the federal government.
Federal agencies are already deep into the complicated rule-making process which will stand behind the actual law.
Senate Minority Leader Mitch McConnell, a Kentucky Republican, wheeled out this week a hand truck stacked with documents that towered over him.
"You know nothing sums up all the excesses of the Obama Administration like Obamacare," he said. "For example, these are the first regulations: 20,000 pages, 7 feet tall, and they're just getting started. Everything they promised about Obamacare isn't coming true."
And as people around the country start to navigate the law, expect the arguments for and against the law from both sides of the aisle to continue.