While she played down the loss of 25,000 jobs in Quebec last month, the Parti Quebecois leader said sovereignty would help the province in dealing with situations such as the pipeline.
The National Energy Board has required Enbridge to ensure the project is "safe and environmentally sensitive."
As she visited Blainville on Day 3 of the campaign leading to the April 7 election, Marois suggested this was a classic example of the province having to play second fiddle to a federal body.
"In an independent, free and sovereign state, we're the ones who would set the conditions," she said. "If we were independent, we could decide what Enbridge has to do with this project."
Marois has asked Quebec officials to analyze the board's decision to ensure the province's demands are being met.
Marois, who has presented her team as a strong manager of Quebec's struggling economy, said February's job numbers reflect just one month and not the overall picture in the province.
She said her government had adopted an aggressive policy that emphasized trade, industrialization and innovative R&D, while under the previous Liberal administration, "there was no economic policy."
Statistics Canada reported Friday that Quebec's unemployment rate rose to 7.8 per cent in February from 7.5 per cent a month earlier.
As the news came out, Marois promised the creation of 172,000 jobs in the province over the next five years.
Her projection came a day after Liberal Leader Philippe Couillard said he would aim to create 250,000 jobs over the same period if he is elected premier.
On Friday, Couillard proposed a project to boost traffic along the St. Lawrence River at a lower cost to make Quebec a key player to receive goods coming into Canada as the result of a free-trade deal with the European Union and an expansion of the Panama Canal.
Couillard said his maritime strategy would create 30,000 jobs over 15 years and generate $7 billion in investment. That would include $4 billion in private investment and $3 billion in public money, half of which would come from the federal government for port infrastructure.
The Liberal leader, who made the announcement on the shores of the St. Lawrence in Levis, said the project is "personal" for him.
"It is important for me because I want Quebec to go to the limit of its possibilities and its dreams," he said.
Couillard said he has already been in touch with the federal government.
"These are not imaginary projects," he said. "Each of these projects has been examined. I know very well that the federal government is very interested in developing trade corridors."
Francois Legualt, who leads the Coalition for Quebec's Future, also targeted the economy but at a more populist level.
He raised once again the idea of a Charter for Taxpayers to ensure citizens get a fair break from government.
Speaking at a daycare centre in Lac-Beauport, Legault made a clear pitch to middle-class families, saying he wants to protect them from governments that are "more and more greedy" and keep "dipping into their pockets."
"Currently, Quebec families wonder what will land on their heads with each budget."
Legault said his government would adopt legislation to limit any hikes in taxes and fees to the inflation rate.
He didn't stop there — he said he'd cut a recently announced increase of 4.3 per cent in hydroelectric rates to 2.2 per cent.
Not everything Friday was tied to dollars and cents.
Marois spent the eve of International Women's Day announcing a flurry of female candidates, including Martine Desjardins, who was a prominent leader during student strikes against tuition fees in 2012.
Desjardins wanted the Liberal government of the day to freeze tuition, while Marois, who was then opposition leader, was in favour of them being indexed to inflation.
— With files from Canadian Press reporters Patrice Bergeron in Levis, Alexandre Robillard in Blainville and Melanie Marquis in Lac-Beauport
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