WASHINGTON — The Supreme Court declared today that same-sex couples have a right to marry anywhere in the United States.

Gay and lesbian couples already can marry in 36 states and the District of Columbia. The court’s 5-4 ruling means the remaining 14 states, in the South and Midwest, will have to stop enforcing their bans on same-sex marriage.

The outcome is the culmination of two decades of Supreme Court litigation over marriage, and gay rights generally.

Justice Anthony Kennedy wrote the majority opinion, just as he did in the court’s previous three major gay rights cases dating back to 1996. It came on the anniversary of two of those earlier decisions.

“No union is more profound than marriage,” Kennedy wrote, joined by the court’s four more liberal justices.

The ruling will not take effect immediately because the court gives the losing side roughly three weeks to ask for reconsideration.