Signed by Barack Obama on March 23, 2010, the Affordable Care Act (ACA) required insurers to accept applicants regardless of preexisting conditions, established state and federal exchanges with income-based premium subsidies, expanded Medicaid eligibility, and imposed an individual mandate to carry insurance. In NFIB v. Sebelius (2012) the Supreme Court upheld the individual mandate as a valid exercise of the taxing power but held that the Medicaid expansion could not be conditioned on loss of preexisting Medicaid funding. King v. Burwell (2015) preserved federal-exchange subsidies. The uninsured rate fell from roughly 16 percent to under 9 percent in the years after full implementation.