A more thorough explanation:

The Defense of Marriage Act (DOMA) is a law passed by the federal government that has three main parts:

1. No state is required to recognize or give legal status to same-sex marriages.
2. The term "marriage" is defined as the union of a man and a woman for federal law purposes.
3. The term "spouse" is defined as only a person of the opposite sex for federal law purposes.

DOMA was created because some people were worried that if one state allowed same-sex marriages, other states would have to recognize those marriages too. By passing DOMA, the federal government made it clear that states did not have to recognize same-sex marriages if they didn't want to.

For example, if a same-sex couple gets married in Massachusetts (where same-sex marriage is legal), but then moves to Texas (where it is not), Texas does not have to recognize their marriage. This means that the couple may not be able to access certain legal benefits that are only available to married couples, such as Social Security survivor benefits or the ability to file joint tax returns.