WASHINGTON — The decision by Massachusetts' highest court to overturn a ban on same-sex marriages "defies reason" and rejects "an understanding of marriage tested over thousands of years and accepted nearly everywhere as the key to a stable society," the Massachusetts Catholic Conference said immediately after the Nov. 18 ruling.

The agency representing the commonwealth's Catholic bishops said in a brief statement that the decision of the Supreme Judicial Court in the case of Goodridge vs. Department of Public Health "must be reversed."

"As devastating as the ruling is, it will not end the debate," the statement said. "We urge the state Legislature to send the Marriage Affirmation and Protection Amendment Act to the 2006 ballot. Thus the people of Massachusetts can reaffirm marriage as the union between one man and one woman, overriding the court's misguided decision in furtherance of sound public policy."

In its 4-3 decision, the court said that "barring an individual from the protections, benefits and obligations of civil marriage solely because that person would marry a person of the same sex violates the Massachusetts Constitution."

The court stayed the opinion for 180 days "to permit the Legislature to take such action as it may deem appropriate in light of this opinion."

Calling marriage "a vital social institution" that both "provides an abundance of legal, financial and social benefits" and "imposes weighty legal, financial and social obligations," the majority opinion by Chief Justice Margaret H. Marshall said the Massachusetts Constitution "forbids the creation of second-class citizens."

The commonwealth, the court said, "has failed to identify any constitutionally adequate reason for denying civil marriage to same-sex couples."

"We are mindful that our decision marks a change in the history of our marriage law," the decision said.

"Many people hold deep-seated religious, moral and ethical convictions that marriage should be limited to the union of one man and one woman, and that homosexual conduct is immoral," it said. "Many hold equally strong religious, moral and ethical convictions that same-sex couples are entitled to be married, and that homosexual persons should be treated no differently than their heterosexual neighbors. Neither view answers the question before us."

If it takes effect in 180 days, the decision changes the law only in Massachusetts.

The majority decision said the Massachusetts Constitution "is, if anything, more protective of individual liberty and equality than the federal Constitution; it may demand broader protection of fundamental rights; and it is less tolerant of government intrusion into the protected spheres of private life."

"This is the wake-up call for both the American public and our elected officials," said Family Research Council President Tony Perkins.

"If we do not amend the Massachusetts State Constitution so that it explicitly protects marriage as the union of one man and one woman, and if we do not amend the U.S. Constitution with a federal marriage amendment that will protect marriage on the federal level, we will loose marriage in this nation," he said.