Robin Sears, who served as chief of staff for then-NDP leader Bob Rae in the 1980s, said NDP governments in Western Canada have historically managed to be fiscally disciplined while remaining socially progressive.
"You don't have to bankrupt a province to be a good progressive I guess is my fundamental point, and I think that's partly what Andrea's is trying to say," he told Matt Galloway, host of CBC Radio's Metro Morning on Monday.
The dissent will only help political enemies of the party — "probably the Liberals," Sears said — adding that this sort of infighting is nothing new to the New Democrats.
Galloway also talked to longtime activist Judy Rebick about Horwath's priorities and the letter NDP supporters signed that warned they may not be voting for the party.
Rebick said Horwath's proposals, such as introducing a "savings and accountability" minister, would unnecessarily move the party to the political right.
"It's like stop the gravy grain," she said, referencing a phrase credited with helping Rob Ford become mayor of Toronto in 2010.
Rebick said supporters also don't like the fact that Horwath has focused on fighting the Liberals, instead of attacking Progressive Conservative Tim Hudak, "the most radical right-wing Tory leader since Mike Harris."
Click here to listen to more of the discussion on Metro Morning.