Final answer:
The 1996 Defense of Marriage Act allowed individual states to deny recognition of same-sex marriages from other states and defined marriage federally as a union between one man and one woman.
Step-by-step explanation:
The 1996 Defense of Marriage Act (DOMA) provided individual states with the authority to deny recognition of same-sex marriages, even when those marriages were legally performed and recognized in other states. DOMA explicitly defined marriage in federal terms as a union between one man and one woman, which led to the denial of various federal benefits to same-sex couples, regardless of their marital status in particular states. Though DOMA did not prohibit states from recognizing same-sex marriages outright, it allowed for the refusal to acknowledge such marriages across state lines, contributing to significant inconsistencies and legal challenges over the years.