MONTREAL -- The woman who could be elected as Quebec's premier in two weeks used a televised leaders' debate to repeatedly attack Prime Minister Stephen Harper, in a hint Sunday of federal-provincial battles that might follow the Sept. 4 provincial election.

From her opening remarks, and throughout the debate, election front-runner Pauline Marois highlighted her strategy of confrontation with the Harper Tories.

The Parti Quebecois leader did not even make a reference to her party's raison d'etre, Quebec independence, in the opening remarks. But she did refer to the prime minister.

"I will never let Stephen Harper choose for us," Marois said, in a reminder of spats with the Tories over employment insurance, justice policy and transfer payments.

"I won't get on my knees before Ottawa like (Liberal Jean) Charest does. And I won't renounce the fight, like (the Coalition party's Francois) Legault."

The PQ has said that if it's elected it will seek a transfer of powers from Ottawa in areas like employment insurance and immigration policy. The party says it will use each refusal from the Tories to build its case that Quebec doesn't belong in Canada.

One of the other debate participants wondered, however, why the PQ leader was so timid about talking about her plan for independence.

In fact that opponent, the co-leader of Quebec solidaire, Francoise David, discussed her own ideas for achieving independence more explicitly than the main sovereigntist figure.

David at one point snapped at Marois: "Attacking Harper is easy. Just about everyone in Quebec can't stand him."

Marois attempted to defend her independentist credentials. She said she would hold a sovereignty referendum "tomorrow morning," if she felt she could.

Throughout the debate the Liberal premier, Charest, repeatedly lumped together his main rivals. He said neither could be trusted or would bring stability on the independence issue.

Some of his most pointed remarks were aimed at Legault, the former PQ minister and now leader of the new Coalition party.

"For 40 years of your life you weren't just an ordinary sovereigntist... you were the most aggressive of the group," Charest said to Legault. "For 40 years you were a sovereigntist. Now for four seconds, you change your mind."

The theme of Legault's abrupt conversion was also raised by his former colleague, Marois, who recalled his once-burning desire to achieve independence. Legault answered that, like many Quebecers, he had simply gotten fed up with a debate that was going nowhere.

"I don't see anyone, on the ground, asking about a referendum," Legault said. "I'm not seeing battles on Montreal buses about a referendum."

Trailing badly among francophone voters, Charest used a two-birds-with-one-stone approach. He kept reverting to themes that could attack both his main rivals simultaneously.

One example of that dual attack came on the issue of corruption.

Battered by two years of scandals, the premier fired back at his opponents with ethics allegations. Charest referred to a six-year-old report that described illegal fundraising schemes in the Parti Quebecois government of 1994 to 2003.

As it happens, Charest's two main rivals in the election -- Marois and Legault -- belonged to that PQ government.

The Liberal premier urged viewers to go online and view the report. He even levelled an allegation of an improper donation to Marois' leadership campaign, with $2,500 from a teenager.

"There's only one case that's been proved, while you're making all kinds of insinuations (about my government)," Charest said.

"There's one proven case of a government that closed its eyes -- and that's the government of which Pauline Marois and Francois Legault were a part... as proven in the Moisan report."

Charest was referring to a report, released by the province's elections watchdog in 2006, that described the PQ improperly receiving $96,400 from the Groupaction marketing firm. The company was best known for its role in the federal sponsorship scandal.

The 2006 report also concluded that the company, through its employees, also donated $8,325 to the Liberals. Corporate donations to parties have been illegal in Quebec since the 1970s.

In recent years the Liberal party has been battered by scandals over its finances -- including the high frequency of donations from employees at engineering firms.

There were also reports of Liberal donors receiving lucrative permits for day-care spaces. The minister once responsible for the day-care program, Tony Tomassi, has quit politics and now faces criminal charges over his use of a credit card supplied by a company that received government business.

"Did you find that normal?" Marois told Charest.

She reminded the premier that when the first controversies surfaced involving Tomassi, his Liberal colleagues would rise to cheer him as he was being attacked in the legislature: "You were getting up to applaud him," Marois said.

Quebec's provincial campaign entered a new phase Sunday with the first in a string of televised leadership debates. It was the first of four debates on four consecutive nights, giving voters a chance to better weigh their options.

Sunday's debate was the only one that will include all four leaders of the biggest parties -- while the remaining ones will feature a series of one-on-ones. The four topics Sunday were: the economy, governance, social policy, the national question and identity.

One-on-one debates are scheduled for Monday through Wednesday, featuring face-offs between Charest, Legault, and Marois.

In Sunday's debate, a frequent theme was attacks on the trustworthiness and preparedness to govern of Legault's new party.

Charest joked that the former PQ cabinet minister couldn't be trusted on the most fundamental of questions. He referred to Legault's recent statement that he would vote against Quebec independence in a referendum -- a statement that stunned some of his old allies.

But Legault replied that the premier was mired in "old battles," playing a tired old tape. He accused his opponents of being obsessed with independence talk and said they were focusing on issues people no longer cared about.

"We will show the door to career politicians," Legault said, during his opening statement.

"It's enough... Things need to change."