Affordable Care Act signed

On March 23, 2010, President Barack Obama signed the Patient Protection and Affordable Care Act in the East Room of the White House after the House of Representatives approved the Senate bill on March 21. The law barred insurers from denying coverage for preexisting conditions, created health insurance exchanges, expanded Medicaid eligibility, and required most Americans to carry health insurance or pay a tax penalty. Obama signed the Health Care and Education Reconciliation Act on March 30, 2010 to revise financing, subsidies, and Medicare provisions that had been left unresolved in the main statute.

The law addressed the long-running political conflict over how the United States would cover uninsured Americans without replacing the private insurance system with a national health service. Democratic leaders such as Nancy Pelosi and Harry Reid argued that the Affordable Care Act built on Medicare, Medicaid, and employer coverage while using federal regulation to expand access and control insurance practices. Republican opponents treated the individual mandate, Medicaid expansion, and new federal rules as an unconstitutional enlargement of Washington's power over health care and private markets.

The Affordable Care Act immediately generated the Supreme Court case NFIB v. Sebelius, in which the Court in 2012 upheld the individual mandate as a tax while limiting mandatory Medicaid expansion. The law's insurance marketplaces opened on October 1, 2013, and Medicaid expansion began on January 1, 2014, making the statute the central framework for federal health policy in the decades that followed.