QUEBEC CITY – After more than 12 years in power, Canada’s scandal-plagued Liberal Party appears set to lose national elections today and be replaced by the resurgent Conservatives.

A Conservative Party victory would mark the end of an era in Canadian politics that saw the ruling Liberals win four successive governments. It is also the culmination of a long rebuilding process for the Canadian right – led by the Conservative leader, Stephen Harper – that saw the merger of two parties in 2003 after a decade of being apart.

The expected Conservative win could mark big changes in relations with America, which have been marked in recent years by acrimony and gridlock on several major files. The Conservatives are likely to bring a less antagonistic approach to dealing with the Bush White House on issues like the softwood lumber dispute and the war on terror.

Polls released over the last week indicated a Conservative lead of about 10 points. That could result in a minority government led by Mr. Harper, meaning his party would need the support of one or more of the three opposition parties to pass legislation in the Canadian parliament. It would mean a Conservative government would have to compromise.

Mr. Harper, a 46-year-old former economist from the western province of Alberta, has run a strong, policy-driven campaign built around five primary issues: cutting taxes, including a reduction of the national consumption tax (GST) by 2%; introducing more accountability measures to government, including limiting party financing and stricter lobbying regulations; cracking down on crime; a child-care tax credit for parents, and guaranteed wait times for certain health care services.

The Conservative leader has also pledged to rebuild Canada’s cash-starved military, reform Canada’s appointed Senate so that senators are elected, and transfer more money from the national government to the provinces, which have the burden of paying for expensive programs like health care and education.

The two-month campaign has been dominated by a strong Conservative performance that has surprised most observers. Mr. Harper appeared down and out after squandering an early lead in the 2004 elections and losing to Prime Minister Martin. But the Conservative leader has spent the last 18 months cultivating a new image, reaching out to new voters, and moving the Conservative Party toward the center of the political spectrum.

The Conservatives have tried to stay away from some of their more divisive positions and have watered down others. While they are in favor of withdrawing from the Kyoto Accord and for revisiting the issue of gay marriage with a free vote in Canada’s parliament, Mr. Harper has backed off previously expressed support for the invasion of Iraq and missile defense. Mr. Harper has also promised not to cut back on key social programs and has said a conservative government would not bring forward legislation restricting abortion rights.

With an inoffensive policy platform and voter anger at the Liberals, the Conservatives are set to win an increased number of seats in vote-rich Ontario. They are also poised to pick up seats in the French-speaking province of Quebec, which has been a virtual wasteland for the party since 1993. Polls predict the party could win upward of five of the 75 seats there today, which would be the best finish in that province for a Conservative leader born outside Quebec since 1965. Liberal support in Quebec has dropped significantly and the separatist Bloc Quebecois still stands to win the most seats there.

Mr. Harper’s accountability proposals have resonated with Canadian voters after a string of Liberal Party scandals. A public inquiry was called in February 2004 by Mr. Martin, to look into supposed irregularities in a sponsorship program established to increase the federal government’s profile in Quebec. The program was set up by Mr. Martin’s Liberal predecessor, Jean Chretien, in the wake of the 1995 Quebec referendum on separation, which saw Quebec nearly vote in favor of independence.

The inquiry reported in November of last year that some Liberal officials acted improperly. Mr. Martin responded by promising that the Liberal Party would pay back about $870,000 in tainted money it had received through the program and banned 10 people for life from the party.

The fallout from the sponsorship scandal and the announcement midcampaign that the Royal Canadian Mounted Police was investigating Mr. Martin’s finance minister over a potential leaked announcement dealing with income trusts hamstrung the Liberal campaign. The launch of the income trust investigation reinforced voters’ perceptions that the Liberals were corrupt.

The Conservatives have also benefited from an unfocused and gaffe-laden Liberal campaign. Before Christmas, Mr. Martin’s communications director attacked the Conservative plan for child-care tax credits by saying Canadian parents couldn’t be trusted with the money because they might spend it on “beer and popcorn.” And last week, during an announcement endorsing the Liberals, a prominent union leader told Quebec voters they should vote for anyone – including the separatist Bloc Quebecois – to stop Mr. Harper.

Mr. Martin, who took over the reins of power in December 2003, had already felt the sting of the sponsorship scandal in the last election, held in June 2004. Upset over the perception of malfeasance and a newly united conservative movement, Canadians reduced the Liberals from a majority to a minority government. That government fell last November, when opposition parties defeated the Liberals on a non-confidence motion.