Donald Trump's boisterous run for the Republican presidency is a reminder not only of his hubris, but the depths to which U.S. political debate can go.

Here in Canada, as the federal parties gird for what is sure to be an equally hard-fought and acrimonious election campaign, we can probably expect to witness a fair bit of partisan rancour — though nothing on a par with U.S.-style electioneering, say political watchers.

There has been "a sharper edge" to Canadian political debate in recent years, says Marcel Wieder, a strategist who has worked with politicians at the federal, provincial and municipal levels. "But there is still a level of civility that exists."

Duff Conacher, co-founder of the advocacy group Democracy Watch and a visiting professor of political science at the University of Ottawa, says that, while more aggressive than in the past, the tone of political discourse here is about 25 years behind that of the U.S., where mudslinging and rumour-mongering are not only rampant but expected.

"Hopefully we don't go down that road," Conacher says.

Some political observers have suggested Trump's recent statements about Mexican immigrants ("they're bringing drugs, they're bringing crime, they're rapists") and his attack on the war record of Arizona Senator John McCain represent a new low for political discourse in that country.

But Conacher says Trump's provocations are just the latest example of name-calling and slander that has characterized American politics for the last 30 years or so.

"Back in the mid-'80s, the U.S. was already heading down the road of people shouting lies at each other on political talk shows. And the political ads were essentially slanderous, with not even the smallest nugget of truth, of a speck of truth," says Conacher.

One of the most egregious examples, he says, was an ad from the 1988 presidential campaign for Republican candidate (and eventual winner) George H.W. Bush.

The ominous clip, often held up as one of the most nefarious attack ads, basically held Democrat candidate Michael Dukakis responsible for the deadly deeds of Willie Horton, a black man who had been released from prison through a furlough program and ended up raping and killing a white woman.

That ad "was just off the scale," says Conacher, adding that the sanctity of free speech in the U.S. is one reason why political debate can often become so hyperbolic.

In addition, the rise of talk radio, along with media outlets more blatantly aligned with political parties, as well as the deregulation of campaign donations, has only intensified the malice in U.S. political debate.

'Different culture'

For his part, Wieder insists that Canada has "a different political culture," even if politicians here are no less interested in gaining advantage over their opponents.

Federal Employment Minister Pierre Poilevre was happy to announce the new $3B in child-care payments on Monday. So happy he wore a partisan golf shirt instead of a suit, which upset some people. (CBC)

With a fixed election date of Oct. 19, the federal parties have been actively trying to discredit their rivals — not least with attack ads.

One of the reasons parties resort to sensational ads is that they know there's low civic engagement, says Wieder.

"Surveys have been done that say Canadians would rather have root canals than talk about politics," he says. "You've got to cut through the clutter to get people's attention and, unfortunately, some of these ads do that."

Even so, there is some evidence that the Canadian public has little patience for political ads that are sophomoric or brazenly misleading.

Robert Soroka, a marketing and management professor at Concordia University, cites the 1993 ad from the Progressive Conservative Party that mocked then Liberal leader Jean Chretien's facial features, the result of a childhood paralysis.

Soroka says the net effect was that "many people who might have considered voting for the Conservatives or who were on the fence might have changed their minds, wanting to dissociate with a party who embraces these tactics."

Another example of a mudslinging ad that backfired, he says, was a Liberal one in the 2006 federal campaign that suggested that, if elected, Conservative Leader Stephen Harper would put soldiers on Canadian streets to help achieve his law-and-order mandate.

Most viewers found the idea inconceivable, Soroka says, adding that "ads that strain believability are not effective."

Characterizing your opponent

These days, the Conservative Party under Stephen Harper has invested heavily in ads that try to frame his opposition opponents, particularly Justin Trudeau, as unfit for the job of prime minister.

Since Trudeau assumed the Liberal leadership in 2013, the Conservatives have been producing ads touting his inexperience and his supposed naiveté on issues such as the legalization of marijuana and combatting terrorism.

Federal Liberal leader Justin Trudeau speaks to children at a space camp in Laval on Monday. How ready is he? the Conservatives want to know. (Ryan Remiorz/Canadian Press)

Earlier this summer, the Conservatives released an ad that spliced together footage from a video produced by the militant group Islamic State alongside that of Trudeau telling a CBC reporter that he would pull Canadian warplanes out of Syria. The message: Trudeau was soft on extremists.

Patrick Gossage, a political strategist and former press secretary to prime minister Pierre Trudeau, called this ad "disgusting," and says its logic actually backfired on the party's image.

Even so, Gossage says the Conservative Party has become quite adept at crafting ads that cast their opponents in an unflattering way without being viscerally negative.

He says the line of ads that characterize Trudeau as "Just not ready" are as effective as the ones that maligned former Liberal leader Michael Ignatieff as "Just visiting."

"When you think about it, it's not really a personal attack," says Gossage. "In fact, it's really just dramatizing what a lot of people think."

In the case of the recent Trudeau ads, "It's just defining him as a young dilettante. It's a lot more calm, less violent than political ads in the United States."