BOSTON (AP) — If the Massachusetts’ high court legalizes gay marriage in a decision due this fall, House Speaker Tom Finneran predicts that state’s legislature will react with a constitutional amendment to ban recognition of same-sex unions.

A previous attempt to change the constitution was supported by more than a hundred thousand voters, who signed a petition in favor of the amendment. The Legislature killed the effort last summer.

“I think there’d likely be a legislative response,” the socially conservative Boston Democrat told The Associated Press. “Last year’s petitions speak to a fundamental concern and level of awareness that exists out there in the body politic.”

Massachusetts’ Supreme Judicial Court is expected to issue a decision this fall in a suit filed by seven gay couples who are seeking the right to marry. Because of the makeup of its court and its past gay rights decisions, legal experts and advocates have predicted that it could become the first in the country to legalize gay marriage.

In making his prediction, Finneran pointed to Hawaii, where a court ruled that it was unconstitutional to bar gay couples from marriage but fell short of issuing licenses. Citizens quickly responded with a constitutional amendment banning gay marriage.

“Now the debate comes to Massachusetts,” Finneran said.

After the demise of the voter-initiated gay marriage amendment last year, state Rep. Philip Travis (D-Rehoboth) proposed another version earlier this year, which Finneran said he supported.

Under the process laid out in the state constitution, no amendment could be placed on the ballot until 2006 at the earliest, meaning that thousands of couples could potentially get married between a favorable court decision and the voters’ verdict.

Any amendment would have to be approved by a joint session of the House and Senate before this two-year session ends, in December 2004, and again during the 2005-2006 legislative session.

This lengthy process could change the dynamic of the debate. Instead of voting on whether to deny gay couples’ rights in the future, citizens would be deciding whether to strip gay couples of rights that had already been granted.

“You will have families who are married and settled,” said Sen. Cheryl Jacques (D-Needham) who is gay. “I think that’s a big step for people to say that should be undone. Opponents of gay marriage will be asking others to affirmatively undo families.”

The high court, which heard oral arguments in the case in March, was expected to issue a decision by early July, under internal guidelines that set a 130-day deadline for a verdict. The court filed a waiver, however, and has given no indication about when the decision may be issued.

To bolster his case in favor of an amendment, Finneran referred to California actor-turned-gubernatorial candidate Arnold Schwarzenegger, who has come out against gay marriage.

“California is known for usually being in the vanguard of social conditions,” Finneran said. “But Schwarzenegger himself said nothing doing on this issue of gay marriage.”