UPDATED January 22, 2015, at 2:05 a.m.

Following a Supreme Court decision last Friday to hear arguments on the issue of same-sex marriage, several Harvard Law School professors predict that the Court will grant a historic constitutional right to same-sex marriage nationwide, but they say a more moderate outcome remains a possibility.

The Court will jointly judge four petitions from Michigan, Kentucky, Ohio, and Tennessee—states where the Sixth Circuit Court previously upheld bans on same-sex marriage—on two separate questions; the first will focus on whether the Fourteenth Amendment requires a state to license same-sex marriages, and the second on whether the Fourteenth Amendment requires a state to recognize same-sex marriages lawfully licensed and performed out-of-state.

“I would guess that the best reading of the tea leaves is that there will be five votes upholding a right to gay marriage,” Richard H. Fallon, a Law School professor, said. He along with Charles Fried and Michael J. Klarman, also Law School professors, identified Justice Anthony Kennedy as the potential “swing vote.”

While the professors interview said that the decision to hear the consolidated cases does not clearly forecast a constitutional right to same-sex marriage, they added that the Court’s recent history does suggest an affirmative answer to the first question. In particular, professors point to the Court’s 2013 ruling to strike down the federal Defense of Marriage Act in United States v. Windsor and its decision in October not to hear appeals to same-sex marriage rulings in five states—a step praised by members of the Harvard BGLTQ community.

Klarman wrote in an email that he feels “confident” that the Court will rule in favor of a constitutional right to same-sex marriage.

“I think there have probably been five votes for gay marriage for a couple of years, assuming the Court took the case. But not all of those five wanted to take the case,” Klarman wrote. “The sixth circuit created a circuit split and apparently that was sufficient to induce enough of the justices to vote in favor of [hearing the case].”

Law School professor and former Supreme Court clerk Laurence H. Tribe ’62 echoed the prediction in an email, writing that the he thinks the Court will “hold that the U.S. Constitution requires universal marriage equality.”

But professors said that the dual-pronged structure of the arguments leaves the Court a more moderate option that would stop short of same-sex marriage in all 50 states. The second question, which addresses recognizing out-of-state same-sex marriages, will only become relevant if the Justices reject the first question of a constitutional right to same-sex marriage.

“They are leaving their options open,” Fried, who served as U.S. solicitor general, said.

Mark V. Tushnet ’67, a Law School professor and former Supreme Court clerk, said that the addition of the second question allows the Court to “deal with the issue comprehensively, no matter the which way the first question came out.”

—Staff writer Andrew M. Duehren can be reached at aduehren@college.harvard.edu. Follow him on Twitter @aduehren.