Stephen Harper tore into the Liberals Friday night during his keynote speech to the Conservative convention in Montreal.

"The Liberal government has been a good government -- for advertising firms and cronies," he said, referring to the sponsorship scandal that's been a plague to the governing party.

Harper avoided addressing his party's internal bickering and set his sights squarely on the Liberals.

Canada is led by "a government under investigation," said Harper to more than 2,500 delegates in attendance at the merged Conservative party's first policy convention.

"For you, politics is a cause, not a racket.

"You are in public life to give, not to take; to build, not to profit; to serve others, not to help yourselves."

Harper also tackled contentious policy markers, including Canada's return to talks with the U.S. on ballistic missile defence -- a program the Liberals seemed to hem and haw over before finally rejecting.

"I tell you that on our common interests with the United States, including on missile defence, our Conservative government will take Canada back to the table -- where it belongs."

Harper also clarified his stance on the controversial issues of abortion and gay marriage that have caused deep divisions among party members.

He promised to support the traditional definition of marriage, triggering a rousing standing ovation from delegates.

But his refusal to bring forth legislation on abortion got him a less enthusiastic response. And he didn't refer to his past promise to allow MPs to introduce a private member's bill on abortion.

In an attempt to reach out to the party faithful who disagree with his stances on these weighted issues, Harper said, "As your leader, if you disagree with me on these matters, I will not call you stupid or label you a threat to Canadian values" -- taking another jab at the Liberals.

"I care less about your views on these matters than whether you are prepared to accept the views of those party members who disagree with me."

He said Martin's Liberal party presents itself as "the great advocate of morality and justice," but added, "Maybe they should start by pondering over the old commandment: thou shalt not steal."

Harper also painted the Liberals as a spendthrift government that's "creating a bureaucratic daycare program so expensive that young couples won't be able to afford children. Promises made, promises broken."

He said the Martin government has no plan to combat the rising dollar, which "threatens jobs in our high-tax economy."

Reporting from the convention in Montreal, Ottawa bureau chief Bob Fife said Harper's speech wasn't just for the ears of Conservatives. "It was also a pitch to Canadians to take a long hard look at the Conservative party before Martin calls an election next year."

Last March, Harper won the Conservative leadership campaign with an endorsement of 56 percent of the party.

Looking ahead to what's expected for Saturday's leadership review vote, Fife said Harper's not expected to reach the 88 per cent level of support that Martin won during the Liberal convention, "but they hope it's going to be over 80 per cent. Anything less could be damaging to his leadership."

With files from CTV News and the Canadian Press