Tuesday and Wednesday, the Supreme Court will dive into back-to-back arguments about gay marriage. These cases that are probably the biggest of the term, and certainly the sexiest. First up is an hour of , the suit challenging the constitutionality of California's voter-approved gay marriage ban. Next comes an hour and 50 minutes on , which takes on the definition of marriage in the federal Defense of Marriage Act. That definition—the union of a man and a woman—denies gay couples more than 1,000 federal benefits that come with marriage, relating to everything from inheritance taxes to health insurance for veterans, even when their marriages are legally recognized in the states they live in.

The arguments will feature top lawyers including Ted Olson (former Bush solicitor general, pro-gay marriage), Paul Clement (former Bush solicitor general, anti-gay marriage), Donald Verrilli Jr. (Obama solicitor general, pro-gay marriage, though the Obama administration is still enforcing DOMA), and Vicki Jackson (Harvard law professor who will argue that the Obama administration doesn't belong in court). What should we watch for to gauge how these cases will come out? Here's my checklist.

Where is Anthony Kennedy?

Kennedy is the swing justice, the one whose vote will probably determine the outcomes of these cases, like so many others. (It must be crazy to have all that power.) As New York law professor Kenji Yoshino has pointed out, there is nothing Kennedy loves more than gay rights and states rights. So Windsor, the DOMA case, is perfect for him. It's the suit in which Kennedy and the court could take an incremental step toward same-sex marriage while also reaffirming states' traditional power over domestic and family law. (The case also features the appealing Edie Windsor, an 83-year-old New York widow who wants back the $360,000 in taxes she paid when her spouse Thea Spyer died—money she would have kept if she'd been married to a man.) Will Kennedy's questions suggest that he thinks New York's definition of marriage should control the federal government?

The California case could be trickier for Kennedy, since it pits a voter-approved same-sex marriage ban, Proposition 8, against the argument that the Constitutions provision of equal protection under the law extends to gay couples seeking the right of marriage. Taken to its logical conclusion, the argument that banning gay marriage is unconstitutional would apply to the entire country—and the laws of 41 states would go down. Olson will try to make it easier by offering Kennedy a way to strike down only Prop 8. The idea here is that California is different from every other state because it allowed thousands of gay couples to marry thanks to a state Supreme Court ruling—and then it took that right away when voters approved the ban. Will Kennedy go for that middle ground? Or will he seem inclined to uphold Prop 8 (the dreaded step backward) or to embrace gay marriage to its national end point, making it (excitingly, but politically prematurely) the law of the land?

Kennedy bonus question: Does he use the word "dignity' in relation to gay rights, as he did in his famous opinion striking down state sodomy laws in 2003? What about the word "animus,' which he used to explain, in 1996, why he thought Colorado voters were wrong—constitutionally wrong—to prevent cities and towns from passing ordinances protecting gay people against discrimination?

Where is John Roberts?

Since Roberts' surprise move last term, when he became the fifth vote to uphold Obamacare, he's had to endure endless speculation about when he'll double down with more squishy rulings. (Wall Street Journal headline: Liberal Man of the Year.) I don't see it—more plausible, I think, is that Roberts bought himself, and the court, the institutional capital to make decisions that are in line with his conservative principles. Still, gay marriage is a winner for the left, politically speaking. One new poll shows national support at a high of 58 percent, and that includes 81 percent of Americans under the age of 30. Even Fox shows a rise to 49 percent, up from 32 percent a decade ago. If Roberts wants to be in sync with the country, he'd vote for striking down DOMA and the California ban too—and if Kennedy is already on board, why not be the sixth vote? Especially because as chief justice, Roberts could write one or both opinions himself, and that way keep them as narrow as possible.

What will Antonin Scalia say?

We know where Scalia stands on gay marriage: He thinks it's immoral. At Princeton last December, a student asked the justice why he makes an analogy between laws against sodomy, bestiality, and murder. Scalia said: "If we cannot have moral feelings against homosexuality, can we have it against murder? Can we have it against other things?' There is no way this man's vote is up for grabs. The only question is how far he goes during oral argument to play to his base and bait his foes. At last month's arguments over the continuing validity of the Voting Rights Act, Scalia talked about the law as "the perpetuation of racial entitlement.' If that's what he says about one of the most heralded accomplishments of civil rights, what spleen will he vent about gayness?

Which test?

When laws treat one class of people differently from another, as Prop 8 and DOMA do, the Supreme Court has a choice. It can strike down such laws only if they have no rational basis. Or it can look more closely, and ask whether the law passes the test of "heightened scrutiny' (the standard in sex discrimination cases) or "strict scrutiny' (the standard when discrimination on the basis of race, ethnicity, or religion is at issue). The justices have never applied one of these higher standards in a gay rights case. But some lower courts have used the heightened scrutiny tests in same-sex marriage cases. Will the justices move in that direction? Personally, I think there's no rational basis for banning gay marriage. The myth that children fare worse when raised by gay parents, for example, has been shredded by social science. But if the court went for heightened scrutiny in the context of gay marriage, that would make it easier for gay people to sue over employment discrimination or mistreatment as well.

Which arguments?

Clement will urge the court to uphold DOMA, and Cooper will argue for upholding the California ban. So what do they say? Do they stick with their strongest argument, about democracy and separation of powers, which is that the court should respect the will of Congress and of California voters? Do they try to show that gay weddings harm heterosexual couples or the institution of marriage—a theoretical claim with no solid evidence? They can't make a religious argument, because that's not how the government gets to justify its laws. And they can't invoke prejudice (nor would they want to, framed that way). But the lawyers could start talking about tradition for its own sake. If you hear that, it's a sign they're getting desperate.

Which parties?

In both cases, the court asked certain lawyers to explain why the parties they represent are the ones who should be here—in legal jargon, the ones with proper standing. In the California case, Gov. Jerry Brown has refused to defend Prop 8. So does the group that put the measure on the ballot (Cooper's clients) get to do that in the governor's stead? Walter Dellinger, Clinton solicitor general and mighty contributor, thinks not. The DOMA case has a different version of the same problem: The Obama administration is arguing that the law is unconstitutional—but it won't give Edie Windsor her tax refund. Does this two-sided position mean Verrilli gets to argue Windsor's side, as he plans to? What about Clement and the House Republicans he represents—are they the right people to defend DOMA? Or, as Professor Jackson will argue, should the court kick this case out for lack of standing and choose a different one, down the line, to decide the constitutionality of DOMA?

I don't find the arguments against standing that compelling. But if a majority of the court does, they could take all the air out of these cases. Maybe that's why I'm betting against this outcome: It's spring at the court, and I'm ready for high drama.