It's not simply that federal New Democrats are furious about what they view as Unifor's betrayal of the provincial NDP.
They're also worried that Unifor could similarly refuse to categorically support the NDP in next year's federal election, thereby endangering the staffers' jobs, which the union is supposed to protect.
Exactly who initiated the divorce is a matter of some dispute.
Unifor national president Jerry Dias said the decision to go their separate ways was "absolutely mutual."
"This will be an amicable divorce," Dias told The Canadian Press.
"Their position is they want to belong to a union that has complete, blind loyalty to the party and I understand that ... But the facts are that one local union within Unifor is not going to dictate the politics of an organization of over 300,000 people."
However, Anthony Salloum, president of the local that represents 600 to 700 NDP political aides, said Unifor effectively pushed the staffers out before they could decide whether to leave.
While Unifor is largely supportive of the NDP, Dias said sometimes its priorities are different than those of the party.
In the Ontario election, the priority was stopping Progressive Conservative Leader Tim Hudak. Hence, Unifor urged Ontarians to vote for incumbent New Democrats or whichever local candidate — NDP or Liberal — was most likely to defeat the Conservative contender.
"The last provincial election was unusual. It's not usually so brazen that you have a Conservative leader that's running on a platform of destroying the trade union movement," Dias said, noting that 800 delegates to a Unifor regional council meeting unanimously called for the union to back strategic voting.
He said there's "no question about it" that the Harper government appears equally committed to destroying the union movement. But whether Unifor will similarly urge Canadians to vote strategically for New Democrats or Liberals to defeat Harper's Conservatives remains to be seen.
That will be up to delegates to a national council meeting this fall, Dias said.
"The politics of how we're going to deal with the next federal election, that decision will be made in September in Vancouver ... There's no question there's some potential parallels (with the Ontario election) but, like I said, we'll cross that bridge when we get there."
Unifor was created a year ago through the merger of the Canadian Auto Workers and the Communications, Energy and Paperworkers unions. The 600-700 NDP staffers on Parliament Hill and in MPs' constituency offices, who had belonged to the CEP, became members of Local 232 of Unifor.
The political aides were uneasy about their new alliance with auto workers from the outset. The CAW had infuriated New Democrats by endorsing Paul Martin's Liberals in the 2006 federal election, in a failed bid to stop Harper from becoming prime minister.
Salloum said Local 232 members had been exploring their options for some time, debating whether to find another union to represent them or stay within Unifor. But the matter came to a head shortly after the Ontario election, which saw Kathleen Wynne's Liberals re-elected as the Conservative vote collapsed.
Dias was invited to attend the local's annual general meeting on June 17 and got an earful about Unifor's refusal to unequivocally back the provincial NDP.
"I think there was tremendous disappointment," said Salloum. "We made no bones about it."
Shortly after that, Unifor's national executive called in the Canadian Labour Congress to act as an intermediary in finding another union to represent the staffers, who remain dues-paying members of Unifor for the time being.
"I think some of our members are concerned with that pre-emptive decision of Unifor National," Salloum said.
Nevertheless, he said the split will be accomplished "amicably and respectfully."
Dias said it's best for both the union and the staffers that they part company.
"It just makes sense for everyone that they find a home that they're more comfortable (in)."
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