Former Quebec cabinet minister Pauline Marois officially announced her candidacy for the leadership of the Parti Québécois on Sunday, a day after Bloc Québécois Leader Gilles Duceppe pulled out.

Duceppe indicated Friday that he wanted the PQ leadership, but told reporters a day later that he was backing Marois, citing a "significant and rapid" swell of support for her.

Pauline Marois greets her mother, Marie-Paule Gingras-Marois, while announcing her candidacy for the Parti Québécois leadership.
(Ian Barrett/Canadian Press)

The Bloc leader also said he didn't want to risk dividing the sovereignty movement by running against Marois, a longtime PQ member who held the province's most important portfolios — including finance, health and education — while the party was in power in the 1990s.

Marois, 58, is now the sole declared contender for the job that opened up when André Boisclair resigned on May 8. Boisclair had been under fire after the sovereigntist party plunged from second- to third-place status in the March provincial election and amid a public spat with Duceppe.

On Sunday, Marois, who applauded Duceppe's decision, told supporters in Longueil, Que., that the party must return to its two main pillars of sovereignty and social democracy.

She also said that any talk of a deadline for Quebec sovereignty needs to be set aside until the party can explain to Quebecers why sovereignty is needed.

"We have to listen to the population, and when we do that, it is possible to discuss how they see sovereignty, what they want for their country," she told reporters.

"And I think it is in this way that we will build the confidence which is necessary to obtain our goal."

Marois had run for party leader on two previous occasions. In 1985, she lost to Pierre-Marc Johnson. She said she was resigning from politics in 2006 after losing her second leadership race in a drawn-out battle with Boisclair that lasted most of the previous year.

A PQ member for more than 30 years, Marois is intimately linked with the party's history. Marois worked as a press attaché for Jacques Parizeau when he was provincial finance minister in the 1970s; she was elected to the national assembly in 1981.

Recent public opinion polls indicate she is the top choice to lead the PQ.

Until a leadership convention can be held, the interim leader is veteran sovereigntist François Gendron.

As for Duceppe, it is expected that he'll receive support from members of the caucus when they meet Monday, Antonia Maioni, a political scientist at McGill University, told CBC News. 

"I think he'll stay on as leader of the Bloc," she said.