The fight for fact-based political debate is a good fight, no doubt. But, like the internet itself, it's also virtually endless.

This week, for instance, an unflattering tweet from a "parody" account mocking Environment Minister Catherine McKenna (and managing to spell her name wrong) bounced around Twitter as if it were actually from her. That came to light shortly after the Conservatives were scolded by observers for a tweet about Liberal tax policy.

Meanwhile, Snopes, the American fact-checking website, was compelled to shoot down a meme that claimed Prime Minister Justin Trudeau had disparaged American farmers. Two weeks ago, Snopes also felt it necessary to fact-check a claim about Trudeau's left eyebrow.

Some of these falsehoods are frivolous. Others might not be.

This is politics in the era of social media, and perhaps a hint of what might come over the next year and a half. To some extent, in fact, Canada is coming late to the problem.

Facebook — which surely has both a moral responsibility and a business imperative to ensure it's not a breeding ground for misinformation — has been confronting the outsized role lies now play in American politics since 2016.

Starting in July, Canada will be one of the countries where fact-checkers hired by Facebook will review some of the links and news stories being shared on the platform.

The limits of fact-checking

This initiative, launched in the wake of the 2016 presidential election in the United States amid widespread concern about the spread of "fake news" and misinformation on Facebook, has been rolled out already in 14 other countries, including the U.S., France and Germany.

In Canada, Facebook is partnering with Agence France-Presse, the international news agency. AFP fact-checkers will review stories that are being shared on Facebook and rate the reports for accuracy. If a story is found to be "false," Facebook will limit its distribution and notify all those who have already shared the story.

Published fact-checks will also be attached as "related articles." And further steps will be taken against pages that are found to repeatedly share false stories (publishers can also challenge or appeal rulings against their stories).

The utility and significance of the initiative has been debated in the United States over the past year, but Facebook argues it can only do so much.

"Over the last 18 months we've made good progress, but we're also aware of the limits of this program," Tessa Lyons, a product manager for Facebook, wrote in a post earlier this month. "Even where fact-checking organizations do exist, there aren't enough to review all potentially false claims online.

"It can take hours or even days to review a single claim. And most false claims aren't limited to one article — they spread to other sites. To make real progress, we have to keep improving our machine learning and trying other tactics that can work around the world."

Right now, the fact-checking applies to news stories — but does not cover images that might carry a political message or purport to show facts.

With the company facing increasing scrutiny over the spread of fake news and hate speech, Facebook says it is devoting more resources to deal with banned content on its site. 13:40

The efforts of human fact-checkers might ultimately enable Facebook's algorithms to better weed out misinformation. And Facebook claims that fact-checking has reduced its audience's exposure to false articles by 80 per cent — but there have been calls for the platform to release more of its data publicly so independent researchers can assess how well the initiative is working.

Fact-checking has proliferated over the last decade. American fact-checking websites like Politifact and Snopes rose to prominence long before "fake news" entered the lexicon. At least one Canadian website, FactsCan, has pursued a similar mandate, but on a much smaller scale.

Competing with the speed of lies

But the rise of social media — which has made it easier to spread misinformation and lies — and the election of Donald Trump (whose disregard for factual accuracy is infamous) have cast the problem in stark relief.

Fact-checking will always have to contend with human bias, partisanship, malicious actors and politicians who insist on their own versions of reality. The truth will always be hard-pressed to catch up with the original lie. For that matter, Trump's victory might suggest that facts have become a secondary concern for many voters.

Of course, it's also possible that Trump's unusually low approval rating has at least something to do with the armies of fact-checkers who continue to pursue him.

But the extent of the challenge shouldn't be underestimated. Indeed, next year's federal election could be a significant test for truth and accuracy, and the ability of Canadian political and media actors to contend with falsehood.

Thomas Jefferson is sometimes quoted as having said that "eternal vigilance is the price of liberty."

Thanks to fact-checkers, we know he didn't actually say that.

Can't argue with the sentiment, though.