What U.S. president signed the Affordable Care Act into law?

President Barack Obama signed the Affordable Care Act into law on March 23, 2010.

Formally called the Patient Protection and Affordable Care Act, the law was enacted by the 111th United States Congress and is commonly known as the ACA or Obamacare. It represented the largest U.S. health-care regulatory overhaul since Medicare and Medicaid were created in 1965.

The law expanded access to coverage through health-insurance marketplaces, premium subsidies, and an expansion of Medicaid for participating states. It also barred insurers from denying coverage or charging more because of pre-existing conditions, and it allowed young adults to remain on many parents’ plans until age 26.

The legislation followed a contentious congressional debate. The Senate passed its version on December 24, 2009, the House approved the final Senate bill in March 2010, and Obama signed it shortly afterward. Many major provisions took effect in 2014 rather than immediately. A common mix-up is confusing the ACA with the later Health Care and Education Reconciliation Act, which amended and supplemented the original law but was not the act Obama initially signed on March 23.