The political action director for the Canadian Labour Congress worked the phones in an unsuccessful attempt to remove NDP Leader Tom Mulcair from the interim leadership of his party in September, according to multiple sources in the party.

Mulcair got wind of the attempted coup and headed it off by confronting the plotters at a caucus meeting at Montreal in mid-September, just before MPs were to head back to the House of Commons for the autumn sitting.

A group of NDP MPs were unhappy with Mulcair’s leadership and wanted to replace him with MP Nathan Cullen, who had agreed to consider stepping in. Mulcair had lost a leadership vote at an Edmonton convention in April 2016, when delegates voted to replace him, but he decided to stay on as interim leader. That summer, he took a vacation in France, and MPs were unhappy that he wasn’t working, raising money and hitting regional media markets, as Rona Ambrose was doing for the Conservatives.

“We saw Rona Ambrose was sort of rejuvenating the party, so there were legitimate questions,” said one MP who spoke on condition of anonymity.

MPs contacted for this story declined to comment on the events because of the tradition of caucus confidentiality, but off the record they described a tense struggle between Mulcair supporters and opponents that threatened to push the leader out of his job.

In late August, as they prepared to meet to plan in Montreal, a group of MPs and party elders decided to try to replace Mulcair. James Pratt, director of political action for the Canadian Labour Congress, agreed to work the phones, telling MPs the party would be better off with Cullen than Mulcair.

“Tom’s gotta go,” said one source familiar with the calls. “He’s ineffective. He hasn’t done anything all summer. The NDP is just sitting around doing nothing. Trudeau’s getting more popular. Those are the kinds of lines he was feeding everybody.”

He was also telling people, according to several sources, that he had enough votes — 22 of the 44 MPs — to push Mulcair out.

“He said he had all the numbers to make it happen,” said an MP. “I don’t know what happened but the numbers that Pratt claimed he had, obviously he didn’t, because Tom stayed.”

Sources say that Mulcair got wind of the calls when MP Niki Ashton let him know that Pratt had called her. Mulcair and his chief of staff, Raymond Guardia, responded by working the phones themselves, calling MPs and lining up support.

“The situation that was facing him was a whisper campaign, to suggest something that wasn’t true, that the majority of caucus was ready to move on,” said a party official. “So the best way to defeat them was to have a loud discussion.”

At the meeting, at the Omni Hotel in Montreal on Sept. 12, Hamilton Centre MP David Christopherson moved a motion for Mulcair to step aside. MPs took turns at the mics, giving their opinions. It soon became clear that the coup-plotters didn’t have the numbers, in part because the party’s 16 Quebec MPs backed Mulcair.

“It was very tense because it was high stakes,” said one MP. “We were going into Parliament two days later and we were in Montreal. And the Quebec caucus were still reeling from the vote. They hadn’t seen it coming. Their concern was reassuring Quebec voters that the NDP was stable.”

Alexandre Boulerice, the high-profile MP for downtown Montreal riding of Rosemont—La Petite-Patrie, is said to have changed his mind, deciding to back Mulcair.

In the end, few MPs spoke in favour of pushing Mulcair out of his leadership role. Erin Weir, the MP for Saskatchewan’s Regina—Lewvan, wanted him to go, as did Brian Masse, MP for Windsor West. But most, it became clear, wanted him to stay on.

“It was set up to be a very high stakes confrontation, and it fizzled,” said one MP.

After it was clear that they didn’t have the votes to force him out, Christopherson withdrew his motion and moved a motion backing him, which was unanimously adopted.

One longtime New Democrat organizer and strategist who was urging MPs to get rid of Mulcair said that caucus members could have made Mulcair’s position untenable had they decided to openly call for him to step aside, but they decided not to go that far.

“In the end, they felt that if they did not have a majority, they did not have the right to express themselves publicly about their concern,” the activist said. “That’s not a view that others shared. It might have been wise for them to rethink that, but they didn’t.”

Many New Democrats say that it is just not their party’s way to stick the knife in a leader.

“It is certainly more in the culture of the tribe to swallow it and either wait for another day or simply forget about it than it would be to go to a mic or to call a reporter and scream blue murder,” said the activist.

Cullen, who had agreed to consider serving as interim leader but had nothing to do with organizing to get rid of Mulcair, said last week that the episode was awkward but necessary.

“We were making history in all the wrong ways at that point, right?” he said. “Our party had never gone through this. The way Tom decided to stay on was a new dynamic, and I think Tom would admit to that.

“A leader has enormous authority that is given to them by party members. The party members had changed their mind and we were about to enter a leadership race. You get used to a certain culture and then that culture has to get adjusted because of the new reality. How decisions get made, who has the final say, question period, all the way down. I think it was a natural and normal thing to readjust all of that.”

Party sources say that Mulcair agreed to work more closely with Christopherson, the chairman of the party’s priorities and planning committee.

Mulcair, a former Quebec Liberal, doesn’t have the tight connections with the labour movement that earlier leaders had. Some of his supporters think that’s what led to the showdown.

“The CLC is torn between the Liberals and the NDP,” said an MP who supports Mulcair. “A lot of those leadership people, (CLC president) Hassan Yussuff and those people and (Unifor president) Jerry Dias, all those labour leaders, they play footsie with the Liberals to a remarkable degree.”

Some MPs were discomfited by the involvement of Pratt, whose job at the CLC had him play a key role connecting the labour movement with the party.

In April, Yussuff called for Mulcair to go, but spokeswoman Kerry Pither said last week that he didn’t ask anyone to rally the votes to unseat Mulcair in September.

“Our president made no secret about his disappointment with Mr. Mulcair’s leadership and spoke about it publicly and in the media,” said Pither. “At no time were any CLC staff directed to play a role in caucus disputes about the party’s leadership.”

Pratt, who is overseas, did not respond to numerous efforts to contact him. He is now said to be a key organizer for Jagmeet Singh’s leadership campaign although the campaign said Friday afternoon that he has no “official role.”