The Supreme Court will hear oral arguments in the challenge to California’s Proposition 8 on March 26 and the Defense of Marriage Act (DOMA) on March 27.

With the arguments fast approaching, the parties’ briefs and amicus curiaebriefs have started to trickle in—tackling the various issues raised in these cases: namely, who can defend these laws and whether the laws violate due process or equal protection.

The government officials charged with defending Proposition 8 and DOMA failed to defend the laws in court, and as a threshold matter, the Supreme Court must decide if advocates of Proposition 8 and the U.S. House of Representatives Bipartisan Legal Advisory Group have standing (a legal term for whether they are the proper parties to defend the laws and have suffered a concrete injury). If the justices hold that the defenders of Proposition 8 and DOMA do not have standing, the Court will not reach the merits of these cases.

Assuming the justices find that the defenders of Proposition 8 and DOMA have standing, they will next consider the underlying constitutional questions: Do the laws violate due process by prohibiting the exercise of a fundamental right, and do laws regarding marriage that treat same-sex couples differently from opposite-sex couples violate equal protection?

The Due Process Clause bans the government from infringing a fundamental right unless it is necessary to further a compelling governmental interest. In a new Heritage Legal Memorandum, John Eastman notes that in Loving v. Virginia (a challenge to the state’s law criminalizing the marriage of interracial couples), the Supreme Court upheld the freedom to marry as “a fundamental freedom that could not be denied on so unsupportable a basis as a racial classification.”

Eastman argues that marriage is fundamental to our very existence because it is rooted in “the formal recognition of the unique union through which children are produced.” In Loving, the Court determined that skin color had nothing to do with that basic purpose of marriage (i.e., producing children). Therefore, the racial classification in Virginia’s anti-miscegenation statute was invidious and unconstitutional. The same cannot be said for same-sex couples.

Equal protection requires that all “similarly situated” classes should be treated alike; thus, as a threshold matter, the Court is faced with deciding whether same-sex and opposite-sex relationships are similarly situated when it comes to marriage. Eastman argues that if marriage were “only about the relationships adults form among themselves, it would undoubtedly violate Equal Protection for a state (or the U.S. Congress) not to recognize as marriage any adult relationship seeking that recognition.” Eastman continues:

But marriage is and always has been about much more than the self-fulfillment of adult relationships, as history, common sense, [and] legal precedent…demonstrate. Because the institution of marriage is the principal manner in which society structures the critically important functions of procreation and the rearing of children, it has long been recognized as one of the cornerstones of our civilized society.

But if the Court finds that same-sex and opposite-sex relationships are similarly situated with respect to the central purpose of marriage, then the justices would need to determine the kind of classification and level of scrutiny involved and whether these laws survive that scrutiny.

With oral arguments scheduled for the end of March, we should expect the Court to hand down its decisions in Hollingsworth v. Perry and United States v. Windsor around the end of June.