Ontario politicians are in preparation mode for next June's election and Premier Kathleen Wynne's Liberal government is laying the groundwork for a narrative to tell voters: Don't let Progressive Conservative Leader Patrick Brown bring "Trump style" politics north of the border.

Her party is accusing Brown of telling lies about Wynne and launching "personal attacks" with a "disgraceful" television ad that Liberals say is inspired by a Republican playbook.

But Brown says the ad simply states the Liberals' record as "politically corrupt" and that Wynne's party is the one that lies.

Legitimate or not, political observers are warning Canadian voters to get used to hearing comparisons to U.S. President Donald Trump ahead of elections here.

"Trump as an insult is easy. It is general, and it is one most politicians are going to throw at each other," said Chad Rogers, a political strategist and commentator in Toronto who worked on the PCs' 2011 campaign.

During the federal Conservative Party of Canada's leadership contest earlier this year, candidate Kellie Leitch was compared to Trump because of her policies on immigration and the way she railed against elites. Leitch didn't seem to mind, and she celebrated Trump's victory, saying his message needed to be delivered in Canada.

Liberals started drawing a connection between the Ontario opposition leader and Trump last month after Brown commented on Wynne's appearance at a trial in Sudbury involving her former deputy chief of staff and another senior Liberal. They are charged with bribery-related offences under the Elections Act.

When Brown talked to reporters about Wynne's testimony, he used the phrases "when she stands trial" and "sitting in trial." Wynne, who is not on trial, is threatening to sue Brown for defamation unless he retracts the statements, which he refuses to do. He says the lawsuit threat is baseless and an attempt to distract from the trial.

'Disgraceful attack ad'

Brown's tactics have no place in Canada, the Liberals say.

"In Canada, we actually expect people to be honest. There is, south of the border, a change in that culture. I do not want to see that change coming to Canada," said deputy premier Deb Matthews last month.

Wynne echoed that view.

"Let's just hope and pray that that's not the level of political debate that we're going to have here in Ontario or in Canada," the premier told reporters.

She said defamation as a political tactic is wrong no matter who's doing it.

"I deplore any behaviour that isn't based on truth … and doesn't deal in honest interaction. No matter who it is — whether it's the [U.S.] president or the leader of the opposition in Ontario — I don't think that behaviour belongs in politics."

Two high-ranking Liberals are charged with bribing potential candidates ahead of a 2015 byelection in Sudbury. Wynne testified as a witness at their trial in September. (Sean Kilpatrick/Canadian Press)

Now the Liberals are pointing to the new ad as further evidence Brown is importing nasty U.S.-style politics.

The spot features Wynne's face on screen as blazing red text and the narrator's voice tell viewers the premier is "untrustworthy" and her party is "politically corrupt."

"Now the premier is testifying at a bribery trial. Just imagine what's next," the narrator says, with a sound effect that evokes a jail cell clanking shut.

Matthews describes it as a "disgraceful attack ad."

"I absolutely believe that [Brown] is taking his cue from Republicans south of the border," she told reporters last week.

"It is not the tradition in Ontario, and he is blatantly lying about Kathleen Wynne and her role in Sudbury," said Matthews.

Logical strategy for Liberals

Matthews rejected the suggestion that negative advertising is par for the course in a campaign season.

"This is not politics as normal in Ontario. In Canada, this is not politics as usual," she said.

But political commentators and observers say it is.

"This style of advertising is nothing new," said Jonathan Malloy, a political science professor at Carleton University.

"It is more rampant in the U.S. and more extreme, but it's a fact of life in Canadian politics."

Brown referred to Wynne 'sitting in trial' during a scrum with media. Wynne has threatened to sue him for defamation if he doesn't retract and apologize for the comments. (Mike Crawley/CBC)

Malloy said Brown and the PCs are trying to build an image of Wynne and the Liberals as untrustworthy and corrupt, a theme Trump hammered at during his campaign against Democratic presidential nominee Hillary Clinton and her party.

The Liberals, meanwhile, are trying to build an image of Brown as someone following in Trump and his party's footsteps.

"I would say it's a logical strategy to try and tie Brown and the PCs to Republican, right-wing politics because they are not popular in Ontario," said Malloy.

Ryan Hurl, an instructor in the University of Toronto's political science department, said it's no surprise Liberals are playing the Trump card.

"There might be fear in Ontario about Trump-style populism and so that might be a useful strategy for the Liberals to pursue," he said.

Negative ads aren't unique to U.S.

But when Canadian politicians accuse their opponents of acting American, they are perpetuating a "Canadian myth" that politics on this side of the border aren't nasty, Hurl said.

Rogers, the political strategist, said all parties use negative advertising, and it's in "no way American in nature."

It's a tense political environment at the Ontario legislature, he said, but anyone there making Trump comparisons is off base.

Brown is brushing off Liberal accusations about his ad.

"The message in that particular ad was about their record," he said.

The Liberals are the ones telling "blatant lies" about him and his party, Brown said, and the ones who are "experts" in negative advertising.

Some Ontario Liberals and political commentators say the tactics Brown and the Conservatives are employing to paint Wynne and her party as untrustworthy and corrupt mimic those used by then U.S. presidential candidate Donald Trump against his Democratic opponent, Hillary Clinton during the 2016 presidential race. . (John Locher/Associated Press)

He cited examples from recent byelections and the last provincial election.

"They ran negative, derogatory, American-style attack ads, and that's how they've governed Ontario for the last number of years," Brown said last week.

Duff Conacher, co-founder of Democracy Watch, says Matthews is misleading voters by saying Brown's tactics are abnormal. "To say it's never been seen before in Canada is blatantly, demonstrably false," he said.

The tit-for-tat between politicians, the constant accusations that the other is a bigger liar, comes with a risk, said Conacher: It turns off voters, and then they don't exercise their democratic duty come election time.

"People know they are being spun and counter-spun," said Conacher, whose group advocates for "honesty in politics law."

"Why pay attention and engage in that?"