The Supreme Court of Canada has ruled that the government has the right to legalize same-sex marriage, but it didn't say whether the current definition of marriage is unconstitutional.

The court's non-binding opinion, which was unanimous in a vote of 9-0, is in reference to four questions on the federal government's proposed legislation changing the definition of marriage.

The court said today that the Charter of Rights and Freedoms clearly protects religious freedoms, but that times have changed and that the legal definition of marriage should also change.

"Several centuries ago, it would have been understood that marriage be available only to opposite-sex couples.

"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."

Prime Minister Paul Martin applauded the decision, and said the government would now move forward with the legislation. He said the bill would be tabled in the House of Commons after the holiday break.

"We are proceeding because quite simply we believe in the Charter of Rights and the guarantee it provides to equality," Martin said in a statement read to reporters in Ottawa.

He said it was a decision he has personally struggled with "but fundamentally it comes down to the equality rights under the Charter."

Three of the questions were put forth by the government under former prime minister Jean Chretien in July 2003.

• First question: Does Parliament have the exclusive legislative authority to change the legal definition of marriage?

Supreme Court's answer: Yes

• Second question: Is extending the capacity to marry persons of the same sex consistent with the Charter of Rights and Freedoms?

Supreme Court's answer: Yes

• Third question: Are religious leaders protected under the Charter of Rights from having to marry same-sex couples?

Supreme Court's answer: Yes

After taking over from the Chretien government, Prime Minister Paul Martin added a fourth question:

• Fourth question: Is the traditional definition of marriage between a man and a woman constitutional?

Supreme Court's answer: The Court exercises its discretion not to answer this question.

Calling the decision a "huge victory" for the Conservative position, Opposition Leader Stephen Harper said he is encouraged by the court's muted rebuke of how the federal government has handled the issue.

"We're encouraged also by the fact that the government was effectively chastised by the court for not appealing lower court decisions."

Justice Minister Irwin Cotler rejected that assessment, saying the court went as far as it could to support the draft bill, and is now handing it over to Parliament.

"They can't direct us as to what we should now do but they've gone as far as they could legitimately go," Cotler said.

He said the court is essentially affirming the decisions handed down by lower courts in seven jurisdictions that ruled that the traditional definition of marriage is unconstitutional.

"Now it's up to us to assume the responsibilities as a government, and happily we've got the Supreme court's support to assume that responsibility."

Martin will hold a "two-line whip" on the vote, meaning cabinet ministers will have to vote for the bill. However, backbench MPs will be free to vote as they choose.

"Individual members of Parliament should be and will be free to vote as they see fit. However, the position of the government is definitive. For that reason, cabinet members will be required to vote in favour of the legislation," Martin said.

Political analysts suggest the bill will likely pass, but only by a small margin.