A proposed debate intended to tackle issues affecting Canadian women has been called off after NDP Leader Tom Mulcair backed away from an early agreement to take part, said an organizer.

“Women’s issues need to be addressed by all parties, not just a few,” said Melanie Gallant, a spokeswoman for Up for Debate, the alliance of Canadian gender equality groups that had been organizing the proposed debate. “As it stands, a common platform for leaders to discuss the challenges faced by women is no longer viable.”

Despite agreeing in principle to the debate, the NDP warned on Aug. 7 that Mulcair would only participate in debates where Harper was also in attendance.

The party issued a list of the debates he would take part in on Aug. 10; it did not include the one on women’s issues.

Liberal Leader Justin Trudeau, Green Party Leader Elizabeth May and Bloc Quebecois Leader Gilles Duceppe had agreed to the debate. Rather than host a debate without the two frontrunners, however, organizers say they will switch gears.

Gallant said that means focusing on organizing debates for local federal candidates and doing everything they can to make sure women’s issues make it onto the public’s radar during the campaign.

“If leaders aren’t willing to answer women’s questions, the rest of their candidates will have to,” she said.

Up for Debate had planned for the debate to cover three topics: ending violence against women, eliminating gender-based pay inequality, and support for women in leadership roles.

The debate would have been the first focused solely on women’s issues since the 1984 debate between Brian Mulroney, Ed Broadbent and John Turner.

Liberal candidate Dr. Hedy Fry, who served as secretary of state for Status of Women from 1996 to 2002, said Mulcair’s decision to renege on his agreement to attend the debate shows he can’t be trusted to prioritize Canadian women.

“This is 52 per cent of the population – we’re not talking about a fringe group,” she said.

Fry says the excuse that Harper also would not attend the debate doesn’t stand up, since “we knew Mr. Harper was never going to participate,” and that the decision shows the party is more focused on trying to get into power than on sticking up for its traditional values.

“This is not Tommy Douglas’s NDP, this is not your mother’s NDP,” she said. “This is a very strategic, calculating NDP.”

News that the debate was being cancelled kicked off a firestorm on Twitter, with many users echoing Fry’s concerns that the decision to back away from the debate suggested the NDP was moving farther away from the values that had drawn many to it in the first place.

Good job, NDP! It's not like half the voting population is something you want to brush off or anything. #cdnpoli https://t.co/OKZlnrKcv0 — Emmett Macfarlane (@EmmMacfarlane) August 24, 2015

Honestly don't recognize this #NDP party – Women’s issues debate called off after Mulcair drops out | iPolitics http://t.co/4qEFQmrsTf — susan king (@suki50) August 24, 2015

Perhaps Mulcair could mansplain to 1/2 the population why skipping this debate on their issues makes sense http://t.co/dyVqpiTxS2 #elxn42 — Jeff Jedras (@jeffjedras) August 24, 2015

History will look not back fondly on the NDP refusing to attend a debate on Women's Issues. #elxn2015 #cdnpoli — Julie S. Lalonde (@JulieSLalonde) August 24, 2015

If your interest in women's issues is contigent on another man's willingness to talk about them….YOU ARE DOING IT WRONG, Mulcair. #cdnpoli — Lucia Lorenzi (@empathywarrior) August 24, 2015

For reference, here is a tweet from Mulcair in November 2014 saying he would attend.