Unifor President Jerry Dias gestures after his election in Toronto, on August 31, 2013. THE CANADIAN PRESS/Galit Rodan

OTTAWA - The NDP's traditionally strong ties to the labour movement won't be enough to secure a blanket endorsement from Canada's largest private sector union in next year's federal election.

Unifor will urge its 300,000-plus members to vote strategically and will pour its resources behind the local candidates — be they NDP or Liberal — best positioned to defeat Stephen Harper's Conservatives.

The union infuriated many New Democrats when it took a similar stance in last spring's Ontario election in a bid to stop Tim Hudak's Progressive Conservatives.

In that case, Conservative support collapsed, allowing Kathleen Wynne's Liberals to cruise to a majority victory.

Unifor national president Jerry Dias says the union has a strong relationship with the federal NDP and will support re-election of all incumbent New Democrat MPs.

But he says the need to defeat the Harper government must trump Unifor's loyalty to the party.

"For us, we know that another four years of Harper will be disastrous for working class people in Canada, period. So, that in itself trumps going out there and putting support in a riding where we know that the New Democrats have no chance," Dias said in an interview.

"If the New Democrats have a legitimate, good shot at winning, absolutely that's where we're going, no question about it. But if there's not a hope in hell, why would I waste resources? It doesn't make a stitch of sense."

For example, in a riding like Manitoba's Brandon-Souris, where the Liberals came within a whisker of defeating the Conservatives in a byelection late last year, Dias said Unifor will throw its support and resources behind the Liberal candidate next year.

"The New Democrat got wiped right out (in the byelection). So for us to even consider supporting the New Democrats in Brandon-Souris, in my opinion, may very well just hand the seat back to the Conservatives."

The decision to pursue strategic voting in the next federal election was taken unanimously at a weekend meeting of Unifor's national council. Ironically, the gathering featured a keynote speech by NDP Leader Tom Mulcair, who announced his plan to reinstate a minimum wage for workers in federally regulated sectors, rising to $15 per hour over four years.

NDP labour critic Alexandre Boulerice conceded Unifor's decision is disappointing.

"Frankly, I would have preferred clear support for the NDP as the real choice for the next election," Boulerice said Thursday.

Still, he said most labour unions are solidly behind the NDP and it's no surprise Unifor is not among them, given its history of strategic voting. Unifor was formed last year from a merger of the Canadian Auto Workers and the Communications, Energy and Paperworkers unions.

The CAW endorsed Paul Martin's Liberals in the 2006 election in a failed bid to prevent Harper from becoming prime minister.

Dias acknowledged the labour movement has no stronger political ally than the NDP. But while Justin Trudeau's Liberals are less supportive of unions than the NDP, he said he doubts they're intent on destroying the movement, as he believes Harper's Conservatives are determined to do.

"So, if my choice is Stephen Harper or Justin Trudeau, then that's a no-brainer."

Dias said anti-union measures are "red meat" that Harper throws out to pacify "right-wing extremists" in the Conservative party.

He pointed to government and Conservative private members' bills which labour advocates complain would impose unfair financial transparency rules on unions, gut public service collective bargaining and make it harder for federally regulated workers to join a union while making it easier to decertify a union.

Unifor's refusal to unequivocally back the New Democrats in the Ontario election prompted more than 600 federal NDP parliamentary staffers, who are members of Unifor, to look for another union to represent them.

Anthony Salloum, president of the Unifor local that represents the staffers, said members will vote early next month to choose a new union home. They have three options: the United Steelworkers, the United Food and Commercial Workers or the International Association of Machinists.

All three "have indicated full support for the NDP," Salloum said.

News from © The Canadian Press, 2014