The Liberal leader and his rival for the Coalition for Quebec's Future clashed in a one-hour televised debate two weeks before Quebecers vote in an election that could spell the end of Charest's career if his party loses power.
With the Coalition eating away at the federalist vote that traditionally goes to the Liberals, Charest's strategy was clear: try to convince voters that Legault, a former Parti Quebecois cabinet minister, is still resolutely sovereigntist.
"When you go negotiate with Ottawa, who are you going to send?" Charest taunted his opponent. "A federalist or a sovereigntist? When you want to be premier of Quebec, you can't be in both camps at the same time."
Legault left the PQ to create his new party, which has no official position on the independence question and promises not to discuss the issue that has dominated Quebec politics since the late 1960s.
Legault has said he will not hold a sovereignty referendum for 10 years and that he would even vote No if a referendum were held right now.
On Tuesday night, he attacked Charest's nationalist credentials — a familar theme for opponents of the former federal Conservative leader.
"We have been divided in Quebec for 30 years," he said. "What we need in Quebec is a nationalist government... a government that defends French, defends our culture, that gets our economy going, that can defend our identity. You have failed in your duties."
Charest retorted that federal transfer payments to Quebec actually fell when Legault was a PQ cabinet minister.
"When I was in federal politics at the same time, I fought federal cuts to Quebec." he said.
Then Charest trotted out what he called examples of his ability to fight for Quebec: a 70 per cent increase in transfer payments since the Liberals came to power nine years ago; the recognition of Quebec as a nation; an "historic" health agreement; and Quebec being represented at UNESCO as part of the Canadian delegation.
Earlier, Charest cast himself as the best politician to lead Quebec in stormy economic times.
"Quebecers have more money in their pockets than nine years ago," he told Legault.
"I want to create 250,000 jobs to have full employment."
Legault fired back that many of the jobs the Liberals have created are low-paying and do not help generate genuine wealth.
"When you came to power in 2003, Quebec was in fourth place (among provinces) in terms of disposable income," he said. "Now, there's just Prince Edward Island that is poorer than us."
The two men kicked off the debate by defending the ethics of their respective parties.
Legault immediately attacked Charest for being too lenient with Tony Tomassi, a Liberal cabinet minister who was responsible for the province's daycare program.
Tomassi was forced to quit politics and now faces criminal charges over his use of a credit card supplied by a company that received government business.
Charest retorted that he acted quickly once he found out about Tomassi's activities.
The Liberal leader then challenged Legault to defend Jacques Duchesneau, a Coalition candidate who, according to Radio-Canada, received anonymous financial donations when he was a municipal politician in Montreal in 1998.
That didn't stop Legault from hammering away at the Liberals' ethics record over the years.
"We've lost the confidence of Quebecers," he said. "And even on the international level, it's embarrassing what Mr. Charest has done."
The Liberal leader shot back that Quebec's international reputation has not been besmirched.
"Internationally, don't worry about Quebec's reputation, Mr. Legault. I know the international scene. Our reputation is intact."
The two men then clashed over the health system, with Legault reiterating his promise to give every Quebecer a family doctor within a year.
"It's incredible how you've treated elderly people over the last nine years," Legault said. "I would be embarrassed in your shoes."
Charest, in his post-debate news conference, lambasted the notion of a family doctor for each Quebecer within a year, saying Legault is trying to put "a chicken in every pot."
But Legault called the proposal realistic.
"I think we have a problem of organization," he told reporters. "It's not a question of not having enough doctors."
The Liberal leader also used his news conference to revisit Legault's 10-year moratorium on referendums and wondered how that strategy would work with Ottawa.
"What kind of agreement does he negotiate? With an expiry date on it that says this agreement is only good for 10 years. After that, we cut you off.
"It doesn't make sense. It's like the old expression, 'If it looks like a duck, if it walks like a duck, it's a duck.'"
The showdown between the two men came two weeks before Quebecers go to the polls Sept. 4.
Charest debated PQ Leader Pauline Marois on Monday night, while Marois and Legault — former PQ cabinet colleagues — will clash Wednesday night.
The only debate featuring all the main party leaders on the same stage occurred Sunday night.
The debates are considered a key test for Legault, who has much less experience than his political rivals when it comes to the cut and thrust of political exchanges on live TV.
The former PQ cabinet minister is a pivotal player in the three-way race that has emerged.
His level of support will likely be decisive in many riding battles, with his party in a position to play the role of spoiler even in areas where it's not likely to win.
The fear of vote-splitting is intense enough on the federalist side that a long-time Liberal organizer in Quebec City is urging party supporters, through different media interviews, to rally behind the Coalition for this one election.
The Coalition is targeting an anglophone electorate that historically votes massively for the Liberals.
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