Few U.S. Supreme Court cases have the potential importance of Hollingsworth v. Perry, to be argued on Tuesday, March 26, and United States v. Windsor, to be argued on the following day. In these cases, the Court will decide whether the millions of Americans who are gay and lesbian have the right to marry. In doing so, the high court will express whether, at last, gays and lesbians are to be treated as equal citizens under the Constitution, and are entitled to equal dignity and respect. Unfortunately, the Supreme Court still does not allow cameras in its courtroom, so we will not able to watch the arguments. Instead, we will have to listen to audiotapes and read the transcripts to learn of the exchanges between the justices and the attorneys, all experienced Supreme Court advocates. What should we look for at the oral arguments? First, how much are the justices focused on whether there is proper standing in these cases? In each case, there is a significant procedural issue that may cause the Court to dismiss without reaching the merits of the right to marriage equality. Hollingsworth v. Perry is a challenge to California's Proposition 8, which amended the California Constitution to provide that marriage in the state must be between a man and a woman. The case was brought by two same-sex couples who wanted to marry. After the federal district court ruled in their favor, the defendants - including California's Governor and Attorney General - decided not to appeal. The supporters of the initiative intervened to appeal and defend the initiative. The California Supreme Court, in its answer to the Ninth Circuit's certified question, said that under California law the defenders of an initiative have standing to defend an initiative when state officials will not do so. But the question is whether that is sufficient to meet the standing requirements of Article III of the Constitution. The Supreme Court long has said that Article III requires a concrete injury for standing; an ideological interest is not sufficient. Do the supporters of Prop. 8 suffer any injury, other than an ideological one, if it is invalidated? U. S. v. Windsor involves a challenge to Section 3 of the federal Defense of Marriage Act (DOMA), which provides that for purposes of federal law and federal benefits marriage must be between a man and a woman. The Obama administration has declared that it believes that this provision is unconstitutional and refuses to defend it. The Bipartisan Legal Advisory Group of the U.S. House of Representatives voted 3-2, along party lines, to intervene to defend Section 3 of DOMA. But the question is whether the House, through this group, has standing to defend a federal law if the executive branch refuses. The questions at the oral argument may give a sense of how likely it is that one or both of these cases might be dismissed on standing grounds. Second, how much do Justice Anthony Kennedy's questions reveal his thinking? The conventional wisdom is that there are four votes for marriage equality on the current Court: Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor, and Elena Kagan. Like so much in current constitutional litigation, the outcome almost surely will depend on Justice Kennedy. There have been two Supreme Court decisions in American history expanding rights for gays and lesbians, Romer v. Evans (1996) and Lawrence v. Texas (2003). Both were written by Justice Kennedy. It will be interesting to see at oral argument whether he invokes these cases. Also, it will be important to focus on whether Justice Kennedy expresses support or skepticism for the arguments put forward by the opponents of marriage equality. The central argument in the briefs against marriage equality is that marriage is fundamentally about "responsible procreation" and that only opposite sex couples can procreate without artificial intervention. Petitioners argue to the Court, "Because relationships between persons of the same sex do not have the capacity to produce children, they do not implicate this interest in responsible procreation and childrearing in the same way. The Equal Protection Clause does not require the State to ignore this difference." It will be important to see whether Justice Kennedy seems sympathetic to this or scoffs at it. The supporters of marriage equality argue that opposite-sex couples always have been able to marry without inquiry as to whether they desired or could have children. Moreover, same-sex couples will have children whether or not they can marry - gay couples through surrogacy and adoption, lesbian couples through artificial insemination and adoption. If marriage is desirable for family stability, as the petitioners claim, then children of these relationships are better off with married parents. Finally, if a majority of the justices seem sympathetic to the idea of marriage equality, it will be interesting whether there are signals as to whether they will rule narrowly or broadly. Will they write opinions limited to striking down Section 3 of DOMA and California's Prop. 8, or will they more broadly proclaim a constitutional right to marriage equality for gays and lesbians that will apply everywhere in the United States? Of course, oral arguments are always treacherous to read. Last year, many interpreted the oral arguments to think the Court was going to strike down the Patient Protection and Affordable Care Act and to uphold Arizona's restrictive immigration law, SB 1070. Exactly the opposite occurred. But the oral arguments will at least give us our first sense of the justices' thinking. Erwin Chemerinsky is the dean and a law professor at UC Irvine School of Law.