Signed into law by President Obama in 2010 and upheld by the Supreme Court in 2012, the Patient Protection and Affordable Care Act fundamentally changes the U.S. health care system by requiring that nearly all Americans have health insurance by the year 2014. Open enrollment for the health insurance exchanges begins October 1, 2013 and coverage is set to begin January 1, 2014. Brookings experts examine how the law may increase quality, access and efficiency in the U.S. health care system over time.