President Obama's re-election will neutralize efforts to overturn the Affordable Care Act, the health care reform law passed in 2010 and one of the signature policy changes of his first term.
The law -- controversial since it was first proposed in 2009 -- requires most Americans to have health insurance and subsidizes coverage for low- and middle-income people.
The fate of health care reform hung in the balance throughout the election campaign, since Republican challenger Mitt Romney vowed to repeal it if elected. Obama won his first big fight over the ACA in June, when the Supreme Court upheld the law.
Several provisions have already gone into effect, including one that provides patients with pre-existing conditions access to insurance and another that allows young adults to stay on their parents' insurance plans.
The country is already feeling the impacts of the law. The number of Americans without insurance this year fell for the first time in four years, according to a U.S. Census Bureau report.
Obama's victory speech in 90 secs
More than 3.1 million young Americans ages 19 through 25 who would otherwise be uninsured now have insurance, according to the Department of Health and Human Services.
Most of the changes, including the new penalty on those who don't have insurance, won't go into place until 2014. But several key pieces of the law will take effect next year.
Starting in 2013, Americans will see two big Medicare taxes that were enacted to help pay for new federal subsidies that millions of people will get when they buy health insurance.
The health reform law adds a surtax on wage income above a certain level and creates a Medicare tax on investment income.
The Medicare tax increases will apply to people making more than $200,000 a year, or $250,000 for married couples.
Those with investment income also could be subject to a new 3.8% tax on at least a portion of their capital gains and dividends.
Roughly 4 million households -- or 2.4% -- will be affected by the surtax initially, according to estimates from the Tax Policy Center. By 2022 that number will grow to 8.3 million, or 4.6% of households.
Also set to roll out next year: The tax-deductible amount a worker may contribute to a flexible spending plan will be set at $2,500 and adjusted for inflation thereafter. As it stands now, there is no official limit, but employers set one for each plan.
By 2014, companies with 50 or more full-time workers must provide health insurance that the government deems affordable and fair, or else they will be subject to fines. Fines are $2,000 per worker, but don't apply to the first 30 workers.