TORONTO -- Canada's Supreme Court ruled Thursday that gay marriage was constitutional, a landmark opinion allowing the federal government to call on Parliament to legalize same-sex unions nationwide.
If approved by a majority of the House of Commons, as widely expected, Canada would become the third country to embrace marriage by homosexuals and lesbians. Belgium and the Netherlands are the other two.
However, the court added that religious officials cannot be forced to perform unions against their beliefs. It also declined to answer a contentious question about whether traditional marriage between men and women also was constitutional.
Prime Minister Paul Martin said after the court's ruling that since judges in six Canadian provinces and one of its territories already allow gay marriages, it should be approved nationwide. He said his government would introduce a bill shortly after Christmas.
He noted that members of Parliament would be free to vote their conscience, but his Cabinet ministers would have to support his bill.
"For many Canadians and many parliamentarians, this is a difficult issue involving personal and religious convictions and it represents a very significant change to a long-standing institution," Martin said.
The court's decision brings to the final stages a long, bitter fight over whether gays and lesbians should be allowed to marry in Canada. Public opinion is evenly divided on the matter, and advocates for both sides are preparing for the final phase of the battle.
"This is a victory for Canadian values," said Alex Munter of Canadians for Equal Marriage.
He said that while public opinion may be split on the subject, Canadians endorse the Charter of Rights and Freedoms, the constitution's bill of rights.
"One area of overwhelming consensus is that the charter is a document that Canadians cherish," Munter said.
In the United States, gay marriage is opposed by a majority of Americans, according to an Associated Press-Ipsos poll taken in November, shortly after constitutional amendments in 11 states to ban same-sex marriage were approved.
"I think it's a tremendously historic day that will help not just families in Canada, but people across the border who are wrestling with this question, of how the denial of marriage harms gay people and their loved ones," said Evan Wolfson, executive director of Freedom to Marry, a gay-rights coalition based in New York.
"Canada is setting a standard for inclusion and fairness, and offering the real proof that ending discrimination helps families and hurts no one."
Wolfson said of Canadians: "We now have the benefit of your wind in our sails, and we are charting the same course."
In California, the Campaign for Children and Families called the Supreme Court opinion "shabby." California's state legislature last week began reconsidering a bill legalizing marriage licenses for gay couples.
To pass in the House of Commons, the legislation needs the approval of about 44 of the 95 Liberal backbench members of Parliament to obtain a 155-vote majority in the 308-seat House.
One top Liberal predicted the legislation should pass easily after its introduction, likely early next year. It already has the support of the 38-member Liberal cabinet and virtually all the 54 Bloc Quebecois and 19 New Democrat lawmakers.
However, some Liberal members of Parliament are opposed.
"I do personally have a problem with redefining marriage and I'm sure some of my colleagues do as well," said Roy Cullen of the Liberal Party.
Gordon Young, pastor of the First Assembly of God Church in St. John's, Newfoundland, was disappointed by the ruling.
"It's a sad day for our country," Young told CBC television news. "God is in the DNA of this nation. We believe that changing the definition of marriage is changing the divine institution that God put in place for the order of our society."
In its ruling, the Supreme Court said the legal definition of marriage should change with public opinion over time.
"Several centuries ago, it would have been understood that marriage be available only to opposite-sex couples," the court said. "The recognition of same-sex marriage in several Canadian jurisdictions as well as two European countries belies the assertion that the same is true today."
The opinion is not legally binding and it now is up to the federal government to make gay marriage protected by law nationwide.
The high court opinion comes 18 months after former Prime Minister Jean Chretien abandoned his government's fight against same-sex marriage by refusing to appeal provincial court rulings in Ontario, British Columbia and Quebec, which declared traditional marriage laws unconstitutional.
His government then drafted legislation that would allow gay and lesbian weddings in city halls, courthouses and in religious institutions that choose to perform them. To ensure the bill would be passed, the Liberal government asked the Supreme Court three questions:
-- Does the federal government have exclusive authority to define marriage?
-- Does the charter protect religious groups from having to perform gay weddings against their beliefs?
-- Is the proposed same-sex marriage law constitutional?
Martin added a fourth question after he was sworn in a year ago: Is the traditional definition of marriage -- between one man and one woman -- also constitutional? This was aimed at clarifying whether the century-old definition of marriage was flawed.
The Supreme Court answered in the affirmative to the first three questions but declined to address Martin's query.