Citizens United v. Federal Election Commission, 558 U.S. 310 (2010), is a landmark decision of the United States Supreme Court regarding campaign finance laws, in which the Court found that laws restricting the political spending of corporations and unions are inconsistent with the Free Speech Clause of the First Amendment to the U.S. Constitution. The Supreme Court's 5–4 ruling in favor of Citizens United sparked significant controversy, with some viewing it as a defense of American principles of free speech and a safeguard against government overreach, and others criticizing it for reaffirming the longstanding principle of corporate personhood, and for allowing large corporations to wield disproportionate political power.
The majority opinion, authored by Justice Anthony Kennedy, held that the prohibition of all independent expenditures by corporations and unions in the Bipartisan Campaign Reform Act violated the First Amendment. The ruling barred restrictions on corporations, unions, and nonprofit organizations from independent expenditures, allowing groups to independently support political candidates with financial resources. In a dissenting opinion, Justice John Paul Stevens argued that the court's ruling represented "a rejection of the common sense of the American people."
