CRS – Same-Sex Marriage: A Legal Background After United States v. Windsor. Alison M. Smith, Legislative Attorney. August 15, 2014.

“The recognition of same-sex marriage generates debate on both the federal and state levels. Either legislatively or judicially, same-sex marriage is legal in more than a dozen states and the District of Columbia. Conversely, many states have statutory or constitutional prohibitions against same-sex marriage. Courts are beginning to address the constitutionality of these “defense of marriage” laws using equal protection and due process analysis. In United States v. Windsor, the U.S. Supreme Court struck down the federal ban on benefits for legally married same-sex  couples. However, the Court indicated that it was taking no position on a state’s authority to  forbid same-sex marriages. Lower courts have interpreted Windsor broadly and have found such bans to violate equal protection and due process principles.”