TORONTO —  The Canadian government introduced its contentious same-sex marriage (search) bill in Parliament on Tuesday, seeking to legalize gay marriage nationwide over the objections of the Roman Catholic Church and other conservative clergy.

Justice Minister Irwin Cotler, upon introducing the bill, said the legislation reflected the spirit of Canadian rights and freedoms protected under the constitution.

"Canada is a land built on a tradition of equality and respect," Cotler said. "It is the responsibility of Parliament to ensure that minority rights are uniform across the country. The government cannot, and should not, pick and choose which rights they will defend and which rights they will ignore."

But the country is deeply divided on the issue, and the bill's passage was not assured.

The opposition Conservative Party said it would fight the legislation, which defines marriage as a civil union between two people, as opposed to the current definition of marriage between a man and a woman.

"Marriage is a historical union that has existed between a man and a woman. It has been recognized in that way by cultures across time," said Vic Toews of the Conservative Party.

Prime Minister Paul Martin (search), whose minority Liberal government drafted the legislation, defended the proposed bill on Tuesday.

"Canada is a country where minorities are protected," he said.

Martin has staked his leadership on the issue, saying he was prepared to call early elections to defend the right of homosexuals to marry.

He insisted a clause in the legislation reinforced a Supreme Court ruling in December that stipulates that no place of worship would be forced to perform gay unions against doctrine.

For passage, the bill needs approval from 154 members of the 308-seat House of Commons. It approved, Canada would join Belgium and the Netherlands as the only other countries to embrace same-sex marriage nationwide.

The debate is being watched closely in the United States, where a majority of Americans oppose gay marriage, according to an Associated Press-Ipsos poll taken in November, shortly after constitutional amendments in 11 states to ban same-sex marriage were approved.

Cotler noted that seven of Canada's 13 provinces and territories already allow marriage between gays and lesbians, and he said it was time to make the law uniform nationwide.

Roman Catholic Church groups have joined forces with other religious groups to defeat the legislation, with Quebec Archbishop Marc Cardinal Quellet (search) saying the bill "threatens to unleash nothing less than cultural upheaval whose negative consequences are still impossible to predict."

The legislation will have to go to committee for study and it could take weeks, or even months, for a final vote.