[Excerpt] This report discusses The Defense of Marriage Act (DOMA) and legal challenges to it. It reviews legal principles applied to determine the validity of a marriage contracted in another state and surveys the various approaches employed by states to enable or to prevent same-sex marriage. This report also examines House and Senate resolutions introduced in previous Congresses proposing a constitutional amendment and limiting federal courts’ jurisdiction to hear or determine any question pertaining to the interpretation of DOMA.