What is State Marriage Defense Act?

Legal Definition
The State Marriage Defense Act (H.R. 3829, S. 2024 in the 113th Congress, H.R. 824, S. 435 in the 114th Congress) is a proposed law introduced by Republican Senators Ted Cruz of Texas and Mike Lee of Utah. that defines the terms "spouse" and "marriage" as used in federal laws to always follow the definition used in the particular state where the law is applied. The bill is advocated by conservative and Christian Right organizations after United States v. Windsor, including the National Organization for Marriage, the Ethics & Religious Liberty Commission, Concerned Women for America, the Family Research Council and Heritage Action.
-- Wikipedia