The ruling cannot be appealed to federal courts because it deals with state constitutional issues, Attorney General Richard Blumenthal said.

Getting a constitutional amendment banning gay marriage on Connecticut's ballot would require the approval of three-quarters of the General Assembly — a highly unlikely prospect, with both houses controlled by Democrats sympathetic to same-sex marriage.

A gay marriage ban also could be approved by a constitutional convention. Connecticut law requires a state referendum every 20 years asking whether it should hold a convention at which delegates would consider rewriting anything in the state's Constitution. The referendum happens to be scheduled for next month, but there is little, if any, appetite for such a move among state leaders, regardless of party.

State Sen. Michael Lawlor, chairman of the legislature's Judiciary Committee, said he expects the General Assembly to pass a gay marriage law next year codifying the Supreme Court ruling.

"It's important that both the legislature and the court weigh in," he said. "The court is saying that it's a constitutional requirement that marriage should be equally available to gays and straights and the legislature should weigh in saying whether or not it's constitutionally required, it's the right thing to do."

The couples who sued said the state's marriage law violated their constitutional rights to equal protection and due process, denying them the financial, social and emotional benefits of marriage enjoyed by heterosexual couples.

Civil unions and a similar arrangement, known as domestic partnerships, are offered to same-sex couples in Vermont, New Jersey, New Hampshire, Oregon, Hawaii, Maine, Washington and the District of Columbia.

Not only do most states bar gay marriage, but voters in 27 states have taken the extra step of approving constitutional amendments to reinforce that prohibition.