"Under DOMA, same-sex married couples have their lives burdened, by reason of government decree, in visible and public ways," Kennedy said.
"DOMA's principal effect is to identify a subset of state-sanctioned marriages and make them unequal," he said.
Some in the crowd outside the court hugged and others jumped up and down just after 10 a.m. EDT Wednesday when the DOMA decision was announced. Many people were on their cell phones monitoring Twitter, news sites and blogs for word of the decision. And there were cheers as runners came down the steps with the decision in hand and turned them over to reporters who quickly flipped through the decisions.
Chants of "Thank you" and "USA" came from the crowd as plaintiffs in the cases descended the court's marbled steps
Kennedy was joined by the court's four liberal justices.
Chief Justice John Roberts, Justices Samuel Alito and Clarence Thomas, and Scalia dissented.
Same-sex marriage has been adopted by 12 states and the District of Columbia. Another 18,000 couples were married in California during a brief period when same-sex unions were legal there.
Copyright 2013 The Associated Press.