The Patient Protection and Affordable Care Act (PPACA), commonly called the Affordable Care Act (ACA) or "Obamacare", is a United States federal statute signed into law by President Barack Obama on March 23, 2010. Together with the Health Care and Education Reconciliation Act, it represents the most significant regulatory overhaul of the U.S. healthcare system since the passage of Medicare and Medicaid in 1965.
The ACA was enacted with the goals of increasing the quality and affordability of health insurance, lowering the uninsured rate by expanding public and private insurance coverage, and reducing the costs of healthcare for individuals and the government. It introduced a number of mechanisms——including mandates, subsidies, and insurance exchanges——meant to increase coverage and affordability. The law also requires insurance companies to cover all applicants within new minimum standards and offer the same rates regardless of pre-existing conditions or sex. Additional reforms aimed to reduce costs and improve healthcare outcomes by shifting the system towards quality over quantity through increased competition, regulation, and incentives to streamline the delivery of healthcare. In 2011 the Congressional Budget Office projected that the ACA would lower both future deficits and Medicare spending.
On June 28, 2012, the United States Supreme Court upheld the constitutionality of the ACA's individual mandate as an exercise of Congress's taxing power in the case National Federation of Independent Business v. Sebelius. However, the Court held that states cannot be forced to participate in the ACA's Medicaid expansion under penalty of losing their current Medicaid funding. Since the ruling, the law and its implementation have continued to face challenges in Congress and federal courts, and from some state governments, conservative advocacy groups, labor unions, and small business organizations.
As of May 2014, approximately 20 million Americans had gained health insurance coverage under the ACA, and the percentage of uninsured Americans dropped from 18% in 2013 to 13.4% in May 2014.