The leader of the People's Party of Canada is claiming that the "authoritarian left" wants to censor and silence anyone who disagrees with it.
That came after a billboard company owned by a man who's hobnobbed with Republican presidents decided not to run a third-party supporter's ads calling for an end to "mass immigration".
Pattison Outdoor Advertising, which is owned by the Jim Pattison Group, stopped carrying the messages following a public uproar.
"The company that owns the billboards has caved in to the leftist mob," PPC Leader Max Bernier declared over Twitter.
That drew a sharp rebuke from Stuart Parker, a former leader of the B.C. Green party.
"So, a contractual arrangement between you & a private company was voluntarily terminated by 1 of the parties because a company felt a continued association w/ you would adversely affect profits?" Parker wrote. "That's not 'left authoritarianism.' It's the free market in action, u whining clown."
According to the CBC poll tracker, the People's Party of Canada has the support of only 2.8 percent of Canadians.
In a written statement, the president of Pattison Outdoor Advertising, Randy Otto, described the public criticism of the ads as "overwhelming".
"As always, we followed the protocol for advocacy advertising as outlined in the advocacy advertising guidelines on our website, when we permitted this ad to be posted," Otto wrote. "That being said, it was never my or Pattison Outdoor's intention to offend, alienate or in any way insult the public by allowing this ad to be run."
He also pledged to review the company's advocacy guidelines, "specifically related to political messaging".
"I regret that the decision we made to allow the ad has been construed to suggest that I or anyone at Pattison Outdoor endorses the message of the advertiser," he added, "that is not the case."
The ads were purchased by True North Strong and Free Advertising Corp.
They were funded by a third-party group, which is run by mining executive Frank Smeenk.
Smeenk has also come under criticism on Twitter.