Legal observers on campus said this week they were not surprised by the U.S. Supreme Court’s decision on Monday to decline to hear a challenge to same-sex marriage in Massachusetts.

The appeal, filed by the conservative non-profit group Liberty Counsel, attempted to overturn the state Supreme Judicial Court (SJC)’s November 2003 ruling legalizing same-sex marriage in the Bay State. Since then, more than 3,000 same-sex couples in Massachusetts have filed for marriage licenses, according to the Associated Press.

The Liberty Counsel cited a clause in the U.S. Constitution regarding “republican” state governments to argue that the SJC’s decision overstepped judicial authority. Instead, the Counsel said, the issue of same-sex marriage should have been decided by popular referendum or the people’s representatives in the legislature.

“Deciding a case that redefines marriage to include same-sex couples is one of those cases that is simply not in the power of the Massachusetts Supreme Court to hear,” said Erik Stanley, the brief’s co-author and chief counsel for Liberty Counsel. Stanley said the Court’s denial was based on the legal grounds of the appeal, not the issue of same-sex marriage.

The Court did not offer comment in its rejection of the appeal.

Harvard professors said yesterday that the Court did not address any significant federal questions relating to same-sex marriage, including whether Massachusetts marriages will be recognized in other states or whether the federal Defense of Marriage Act is constitutional.

“I think the ruling is really insignificant,” said Williams Professor of Criminal Justice Richard D. Parker. “It has nothing to do with the issue.”

Tyler Professor of Constitutional Law Laurence H. Tribe ’62 said that he had expected the Court to reject the Liberty Counsel’s claim.

“That argument is completely without merit and was bound to convince none of the Court’s nine justices....Claims that giving the state judiciary this sort of power violates some separation-of-powers norm binding on the states are entirely frivolous,” Tribe wrote in an e-mail. Tribe filed an amicus brief in January urging the SJC to support same-sex marriages.

Peter Renn, the co-president of Lambda, a gay student organization at Harvard Law School, agreed that the decision was predictable and said the appeal “wasn’t a very worthy claim.”

“The weakness of the case demonstrates how desperate opponents of marriage equality are and the flimsy legal arguments that they must resort to in order to justify prejudice,” Renn wrote in an e-mail.

The ruling ensures that the legal battle over gay marriage will remain below the federal level for now, although President Bush has advocated for a federal constitutional amendment banning same-sex marriage.

Professor of Law David Barron ’89, also a former Crimson president, said the Supreme Court may eventually take up the issue of same-sex marriage if more states followed Massachusetts’ lead and brought the issue to the forefront—but he didn’t envision it happening in the near future.

“I’d be surprised if at this stage they’d be interested in hearing such a case, and I’d be surprised if litigants of the gay rights movement would present such a case to them [now],” Barron said.

Stanley said Liberty Counsel has two dozen lawsuits on same-sex marriage currently pending in state trial and appellate courts.

“We’re going to continue to protect traditional marriage in those lawsuits,” Stanley said.

The group has filed a lawsuit with the Massachusetts SJC asking the court to overturn its ruling, but Stanley admitted that suit would “probably not” succeed.

The Massachusetts State Legislature granted preliminary approval in March to a state constitutional amendment banning same-sex marriage but allowing for civil unions. The amendment must be passed again by next year’s Legislature before being put to a statewide ballot referendum.

“I think the lack of public uproar in Massachusetts is telling—the sky didn’t fall on May 17,” said Cambridge City Councillor Brian P. Murphy ’86-’87, referring to the date when the state first issued marriage licenses to same-sex couples.

“I hope that the legislature recognizes this, and does not continue with the attempt to deny one group of people equal treatment by referendum,” added Murphy, who co-sponsored a resolution in February that paved the way for Cambridge to become the first city in the Bay State to issue the licenses.

—Staff writer Michael M. Grynbaum can be reached at grynbaum@fas.harvard.edu.

—Staff writer Jessica R. Rubin-Wills can be reached at rubinwil@fas.harvard.edu.