U.S. Attorney General Eric Holder, in a column appearing in USA Today:

Over the next several months, the Supreme Court will decide whether state restrictions on same-sex marriage are unconstitutional. As the court considers that momentous question, the Department of Justice will make clear that our answer is an unequivocal “yes.”

This week, the Justice Department will file a brief setting forth our position that state bans on same-sex marriage violate the fundamental constitutional guarantee of “equal protection of the laws.” It is clear that the time has come to recognize that gay and lesbian people deserve robust protection from discrimination.

Nothing justifies excluding same-sex couples from the institution of marriage. Denying them the right to marry serves only to demean them and their children, to degrade the dignity of their families and to deny them the full, free and equal participation in American life to which every citizen is entitled.