By Sam Baker

The Supreme Court this week will dive into the biggest civil rights issue it has faced in a generation — whether same-sex couples have the right to marry.

The court will hear oral arguments Tuesday and Wednesday in a pair of cases with enormous historical implications for the nation, the court and the legacy of Chief Justice John Roberts.

The Roberts court is no stranger to politically charged issues — from campaign finance to healthcare to affirmative action and voting rights. And same-sex marriage is among the most polarizing debates of the past 20 years.

But this week’s cases go further, raising fundamental questions of equal protection in terms more stark than the court has tackled in years.

Although both cases deal with same-sex marriage, they raise distinct questions.

On Tuesday, the court will hear arguments in a challenge to California’s ban on same-sex marriage, known as Proposition 8. 

If they want to — and that’s a big “if” — the justices will have an opening in the case to declare that the Constitution ensures a right to same-sex marriage in every state.

Wednesday’s case is a challenge to the Defense of Marriage Act (DOMA), the federal law that prohibits same-sex couples from receiving any federal benefits for married couples (such as tax preferences and military burials).

Here are five things to watch as the arguments play out next week:

1.The drama

The justices love to downplay the politics surrounding their work, but the story of their same-sex marriage cases could have come straight from an Aaron Sorkin script.

They’re taking up a polarizing social issue just as public opinion and political consensus has flipped. 

Former President Clinton has said the court should strike down a law he signed, and President Obama last year stated support for gay marriage — a reversal on the issue in the time since these lawsuits began.

The attorneys making the most aggressive argument for same-sex marriage are an odd couple: Ted Olson, a star of the conservative legal world who represented former President George W. Bush in Bush v. Gore, and David Boies, who represented former Vice President Gore.

 Olson’s successor in the Bush administration, Paul Clement, is on the other extreme, defending DOMA on behalf of Speaker John Boehner (R-Ohio). He’ll be facing off against Solicitor General Donald Verrilli, a rematch from the court’s landmark healthcare case. The DOMA arguments falls on the same date, one year later, as those in the healthcare case.

 2. Anthony Kennedy

Once the arguments begin, the five most important things to watch will be Anthony Kennedy, Anthony Kennedy, Anthony Kennedy, Anthony Kennedy and Anthony Kennedy. No one doubts that he holds the key to the outcome. Lawyers and reporters inside the court this week will be picking apart his every word for clues.

Kennedy is widely seen as a reliable vote to overturn DOMA, largely because of his opinions in two earlier cases overturning state laws that discriminated against gays and lesbians.

In a 1992 case, Kennedy struck down a Colorado law on the grounds that “homosexuals are forbidden the safeguards that others enjoy or may seek without constraint” — which is exactly what critics see in DOMA and Proposition 8.

But Kennedy is also skeptical of federal and judicial overreach. He’s often described as a libertarian — and that raises questions about whether he might be inclined to strike down DOMA, the federal law, but leave the broader question of marriage rights up to the states.

3. How far is the court willing to go?

A decision striking down DOMA would allow same-sex couples to collect federal benefits in states that recognize same-sex marriage. And while that would be a big step, it would still allow states to outlaw same-sex marriage. That’s where the Proposition 8 case comes in.

Olson and Boies argue that the Constitution ensures the right for all couples to marry, in every state, and no state can interfere with that right.

“The whole purpose of the 14th Amendment was to take away from individual states and their voters the right to discriminate … You can’t just say we’re going to allow every state to wait as long as it wants to recognize basic constitutional rights,” Boies said.

But the court (or, more specifically, Anthony Kennedy) might not want to go that far, and it has several more narrow options to choose from. 

The Justice Department says the court should rule that a state can’t outlaw same-sex marriage if it provides same-sex couples with all the legal benefits of marriage. 

Another option would only apply to California.

And, of course, the court could also uphold Proposition 8, saying the Constitution does not trump the ability of California voters to make this decision themselves.

4. What’s the purpose of marriage?

The whole ruling might hinge on this question. Same-sex marriage proponents say marriage is a fundamental right. Lower courts in the DOMA case have agreed, and it’s a view that would require the court to approach DOMA and Proposition 8 with extra scrutiny.

DOMA’s supporters, though, say marriage isn’t a fundamental right, but rather an institution the government created to serve the goal of promoting procreation.

John Eastman, chairman of the board of the National Organization for Marriage, said states have the right to make their own laws to encourage people to have children.

“I think there’s this over-arching issue of whether this is a civil right, that the court should decide against majority rule, or a policy decision,” he said.

As long as the court agrees that reproduction is a key function of marriage, Eastman said, DOMA and Proposition 8 could stand.

“Do we think the procreative purpose continues to be a core part of the purpose (of marriage)? That basic policy judgment is what’s on trial here,” he said.

David Gans, civil rights director at the Constitutional Accountability Center, said the court has rejected that view of marriage in the past.

States don’t prohibit marriage among infertile couples, or couples who are too old to have children, he noted — meaning the institution is already open to people who could not help the state achieve a goal of promoting procreation, so there’s no reason to close it off to same-sex couples.

5. Will they rule at all?

The justices set aside nearly an hour on Wednesday for debate over whether they can even make a ruling in the DOMA case. There’s a question over whether the group defending DOMA has “standing” — the right to participate in the case.

Normally, the Justice Department defends federal laws before the Supreme Court. 

But that option disappeared after the Obama administration decided DOMA is unconstitutional. Congress could defend its own laws, but there’s no legal entity that speaks for the entire Congress, as an institution.

The group defending DOMA this week basically represents Boehner and other House Republicans. And the Supreme Court has previously ruled that individual lawmakers can’t challenge laws they don’t like.

Likewise, the state of California isn’t defending Proposition 8. 

The state Supreme Court said it’s OK for a group of Prop 8 supporters to take up the task, because it passed as a ballot initiative, but the Supreme Court doesn’t necessarily have to follow that interpretation.