Jeff Zarrillo, left, and Paul Katami are two of the plaintiffs in the same sex-marriage case that is going to be heard by the Supreme Court. (Bret Hartman/For The Washington Post)

With an overwhelming majority of state laws pointing one way and public opinion trending rapidly in the other, the Supreme Court may enter this week’s historic arguments over same-sex marriage with a preference for caution over boldness.

Two cases — Tuesday’s involves California’s ban on such unions, Wednesday’s concerns Congress’s decision to withhold federal recognition of legally married same-sex couples — offer the justices an unusually wide range of options. A broad constitutional ruling is one possibility, but so is a finding that the cases are not ripe for decision.

But the court’s first full examination of whether the right to marry must be extended to same-sex couples puts on full display the justices’ official responsibility as arbiter of the Constitution, as well as its unofficial role as interpreter of the nation’s readiness for social change.

Proponents of same-sex marriage say conditions could not be better for the issue to reach the nation’s highest court.

“Everything seems to be breaking in support of marriage equality,” said Theodore J. Boutrous, an attorney for two California couples challenging that state’s ban on gay marriage.

The Post’s Chris Cillizza is joined in a Google Hangout by Post SCOTUS reporter Bob Barnes, GLAD’s Mary Bonauto, The Advocate’s Matthew Breen, Heritage Foundation’s Ryan Anderson and SCOTUS blog’s Amy Howe to discuss the cases ahead of the Supreme Court hearings. (The Washington Post)

He points to the growing number of states that now authorize same-sex marriage, the shifting stances of the nation’s political leaders and polls that show a majority of Americans now favor a concept of marriage that did not exist anywhere in the world until 2000.

“I think the direction of the country is clear,” Boutrous said.

Other supporters worry about asking the Supreme Court to do too much too quickly. Some in particular are nervous about recent comments from Justice Anthony M. Kennedy, who wrote the court’s two most important rulings in favor of gay rights and who will almost certainly be crucial in the coming marriage cases.

Kennedy told a questioner he did not find it ideal that the court was recently at the center of so many important questions on social issues and civil rights.

“A democracy should not be dependent for its major decisions on what nine unelected people from a narrow legal background have to say,” Kennedy said.

Indeed, the low-key court briefs filed by those opposing same-sex marriage seem to go out of their way to acknowledge the political victories of same-sex marriage proponents and the country’s rapidly changing mood on the issue. But they are cited as reasons that the court’s intervention is unneeded.

“With an issue as fast-moving and divisive as same-sex marriage, the advantages of the political process are substantial,” wrote Paul D. Clement, who is representing Republican House leaders in their defense of Congress’s 1996 decision to deny federal recognition of same-sex marriages performed in the states where they are legal.

Charles J. Cooper, who represents proponents of Proposition 8, which added the same-sex marriage ban to California’s constitution in 2008, agreed in his brief to the court that persuasion and compromise in the political arena are preferable to a judicial solution.

“Decisions reached through this process are more likely to be regarded by a free people as legitimate and be widely accepted than decisions reached in any other manner,” he wrote.

Gauging public sentiment

Barry Friedman, a New York University law professor who argues that the court’s major decisions eventually align with public sentiment, said the same-sex-marriage cases are particularly vexing for the court. “Gay rights cases have been an area in which the Supreme Court has tended to be particularly in touch with public opinion,” said Friedman, who wrote about public opinion and the court in his book “The Will of the People.”

But is public opinion best represented by the fact that four-fifths of the states forbid same-sex marriage, with a majority of those going so far as to write the prohibition into their state constitutions? Or is momentum headed the other way?

While in 2012 North Carolina added a prohibition against same-sex marriage, voters in three states decided to allow it — the first instances in which gay nuptials were approved in a popular vote. Nine states, including Maryland, plus the District, now allow same-sex marriage.

Colorado recently approved civil unions for gay couples, and a marriage bill has passed one house of the Illinois legislature. A recent Washington Post-ABC News poll showed 58 percent of Americans favoring legalization of same-sex marriage, including more than 80 percent of adults younger than 30.

Two cases from the court’s past — neither touching on the issue of gay rights — offer lessons about the consequences of a broad ruling, advocates say.

One is Roe v. Wade, the court’s 1973 constitutional ruling that swept away states’ ability to prohibit or restrict abortion in early stages of pregnancy. It is cited in many of the briefs filed before the court as a warning of a judicial intrusion into the political arena that prolonged division rather than concluding it.

A broad finding that the constitutional right to marriage must be extended to same-sex couples — which is what the California couples request — would force a national solution on a nation not ready for it, opponents say.

Former federal judge and conservative legal scholar Michael McConnell laid out what he and other see as Roe’s legacy in a recent op-ed in the Wall Street Journal.

“We learned from Roe v. Wade that the Supreme Court endangers its own legitimacy and exacerbates social conflict when it seeks to resolve moral-legal questions on which the country is deeply divided without a strong basis in the text of the Constitution,” McConnell wrote.

Others argue that it is abortion that is controversial, not the court’s ruling, and Boutrous contends the analogy “completely falls apart if you look at it closely.”

Roe, he told reporters in a conference call last week, “in essence came like a bolt out of the blue to the American people.” The notion of same-sex marriage, despite its brief existence, has been thoroughly debated, he said.

1967 marriage case

Boutrous and others on the side of same-sex marriage said the proper comparison is to Loving v. Virginia, in which the court in 1967 struck laws banning interracial marriage. While it seems the majority of Americans are now tolerant of same-sex marriage, polls then showed more than 60 percent of the country opposed to mixed-race marriages, said David Boies, one of the lawyers arguing for the constitutional rights of same-sex couples.

“But when that decision came down, there wasn’t a ripple, there wasn’t any disruption,” Boies said. “Everybody simply accepted it . . . because they fundamentally knew it was the right thing to do. The same thing will become true here.”

Those who oppose same-sex marriage said that Loving did not change the fundamental nature of marriage as being between a man and a woman and that the number of states that banned mixed marriages was a fraction of the number that prohibit same-sex marriage.

All of which could point to a go-slow approach — and the court has left itself plenty of options.

The broad constitutional question about the right to marry is raised only in the California case. But the court could decide whether California voters have the right to amend the state constitution without deciding the federal question.

Or it could find that since California officials have declined to defend Prop 8, the case is not properly before the Supreme Court. That would leave in effect a lower-court decision overturning the same-sex marriage ban but limit the decision to California.

There are similar technical questions in the Defense of Marriage Act case, since the Obama administration believes the 1996 law is unconstitutional and has declined to defend it.

Two justices will get the most attention in this week’s oral arguments. Kennedy is the court’s most outspoken advocate of states’ rights. But he also provided the critical vote and employed soaring rhetoric in writing the opinions striking down a Colorado initiative that would have denied discrimination protection to gays and objecting to state sodomy laws that targeted homosexuals.

The other is Chief Justice John G. Roberts Jr. His conservatism would seem to weigh against same-sex marriage, but as chief justice he also worries about the long-term influence of the court on a subject in which the public mood is clearly in flux. “He particularly may look for a way to avoid ruling against gay marriage in these cases, ” Friedman said, “even if he is not prepared to rule for it.”