CANDIAC, QUE. -- Liberal Leader Justin Trudeau went on the offensive against Conservative Leader Erin O'Toole and Bloc Quebecois Leader Yves-Francois Blanchet on Sunday, even as he continued to face questions regarding the treatment of two of his own former MPs.

Trudeau spent a second straight day targeting Bloc-held ridings on Montreal's South Shore, where his party hopes to regain some of the ground it lost in 2019.

Trudeau was in the La Prairie riding near Montreal on Sunday, a seat the Liberals lost to the Bloc's Alain Therrien in the last election. As he spoke at a park in Candiac overlooking the St. Lawrence River, he hammered home his commitment to Quebec and the fact that only his party, and not Blanchet's, can form government.

Trudeau said Blanchet has a mixed record of standing up for the environment and "has not been particularly strong or clear" in pushing for COVID-19 vaccination.

"I think Mr. Blanchet is struggling to be relevant on any of those big issues because he can speak for Quebecers, but so do we," Trudeau said. "Except we can deliver for Quebecers."

At dissolution of Parliament, the Liberals held 35 seats in Quebec compared to 32 for the Bloc. The Conservatives held 10 and the NDP had one. Gaining more seats in Quebec will be key to Trudeau's hopes of returning to majority status.

But the Liberal leader's campaign has been hampered in recent days by criticism from Quebec Premier Francois Legault, who has said the federal Liberals, NDP and Greens have an overly centralized approach that would weaken Quebec's powers.

Trudeau said Sunday that while he and all Quebecers may not always agree on a vision of federalism, he believes their values align on issues such as the environment, gun control and COVID-19 vaccination.

But Trudeau also doubled down on another issue in which he and the Quebec premier have been at odds.

He told reporters that he remained open to participating in an eventual court challenge against Quebec's secularism law, which bans some public servants from wearing religious symbols on the job.

A ruling on the law, called Bill 21, is currently being appealed, and Trudeau said any federal intervention would only come after that process is completed.

"We have not taken off the table intervening at a later date because no federal government should take off the table the ability to stand up for people's fundamental rights," he said.

As much as Trudeau wanted to talk about Quebec, he could not escape questions about former justice minister Jody Wilson-Raybould's tell-all book that touches on the criminal prosecution of Quebec engineering giant SNC-Lavalin, which was facing bribery charges related to contracts in Libya.

Wilson-Raybould would later testify that senior party leaders wanted her as attorney general to stop the prosecution for political reasons.

Trudeau said the matter had been thoroughly dissected in parliamentary committee hearings, newspaper articles and other testimony prior to the last federal election in October 2019. He said the RCMP had never contacted him regarding the SNC affair.

Similarly, Trudeau brushed aside a question about former Liberal MP Celina Caesar-Chavannes and comments she made in an interview that aired Sunday on The West Block. In it, she said she planned to support her local Conservative candidate due to her disappointment with Trudeau.

"I wish Celina all the best," Trudeau said Sunday. "People have a really important choice to make in this election."

Trudeau repeatedly pivoted to target O'Toole, who he blasted for failing to mandate mandatory COVID-19 vaccinations for his candidates.

Trudeau also stressed his own party's promise to get daycare costs to an average of $10-a-day nationally within five years, as well as a $6 billion child-care agreement his party signed with Quebec. He attacked O'Toole for planning to axe the plan in favour of a system of tax credits, which Trudeau said would hurt women's ability to participate in the workforce.

"Mr. O'Toole wants to take it back to 1951, apparently," he said.

Trudeau also criticized the NDP, saying the party's recently released costed platform that depends largely on taxing the ultra-wealthy doesn't stand up to closer scrutiny. He also took aim at the People's Party of Canada, which he likened to the kind of "divisive" and "polarizing" populist movements that have been rising in the United States and elsewhere.

Trudeau was greeted by a small crowd of supporters who cheered him warmly at the riverside park. There was also one lone protester, who yelled loudly that Trudeau was a "traitor" and let out a cheer when the name of People's Party Leader Maxime Bernier was mentioned.

Later, Trudeau marked a return to high-energy campaign rallies -- with a pandemic twist -- as he hosted an event at a drive-in movie theatre in Oakville, Ont., alongside Toronto-area candidates Anita Anand, who has served as procurement minister.

The partisan crowd, some of whom donned maple leaf ponchos to ward off the rain, cheered and honked their car horns as Trudeau attacked O'Toole for failing to require candidates to be vaccinated and urged supporters to vote Liberal if they want the pandemic to end for good.

This report by The Canadian Press was first published Sept. 12, 2021