The Supreme Court will hear arguments on two cases later this month, and thereafter they will sanction same-sex marriage. Here’s why.

In the first case, two same sex couples sued the state of California, which denied them the right to marry. California’s Proposition 8 modified the state constitution and defined a valid marriage as only between a man and a woman.

In the second case, a woman whose same-sex spouse died was made to pay inheritance taxes because the government, relying on Section 3 of The Defense of Marriage Act (DOMA), claimed the woman was not legally married, and thus could not take assets from someone she identified as her deceased spouse without incurring the taxes. The woman, Edie Windsor, was made to pay taxes. Two lower federal courts found the section unconstitutional and ordered a refund.