Anti same-sex marriage protesters hit the streets of Ottawa Saturday, and they targeted one senior Liberal in particular -- Joe Volpe.

The immigration minister and Toronto MP was the object of a full-page newspaper ad in the National Post asking, "Can we trust Joe Volpe?"

A new website, defendmarriage.ca, has a video clip of Volpe in a church about 18 months ago promising to defend traditional marriage.

Volpe joined cabinet in December 2003 after Paul Martin became prime minister. He became immigration minister in January after Judy Sgro stepped down to fight allegations against her.

"As soon as he got his cabinet post, as soon as he got the salary increase and the perks and the power that goes with it, he said never mind," Charles McVety of the Defend Marriage Coalition told his supporters.

Martin has ordered his cabinet ministers and parliamentary secretaries to support the government's same-sex marriage legislation. Backbench Liberal MPs are free to vote as they wish.

"No, I think they're wrong about betrayal," Volpe told reporters.

Volpe says he kept his word by making sure religious groups wouldn't be forced to perform gay marriages.

"Here's a member of Parliament who became a cabinet minister who was able to shape legislation to reflect their concerns, protect their interests," Volpe says.

Inside the Liberal Party's biennial policy convention, the 2,500 delegates overwhelmingly voted to endorse the government's same-sex legislation.

When one delegate yelled after the vote, "What's next: pedophilia?" he was roundly booed by the crowd.

The party had previously voted to uphold the traditional definition, but numerous delegates said times have changed.

Numerous court decisions have held restricting civil marriage to a couple composed of a man and a woman violates the equality rights of gays and lesbians under the Charter of Rights and Freedoms.

The federal government's legislation is designed to acknowledge this legal reality and make the definition of marriage standard across the country.

While the legislation is expected to pass, the Conservative Party opposes it, as do some socially conservative Liberal MPs.

With a report from CTV's Roger Smith