There is an unwritten but well understood rule in Canadian politics, in fact it stands for most Western countries — you don’t attack your political opponent on foreign soil.

The idea goes that as much as politicians may disagree here at home, there is a united front on the international stage.

Consider it the grown up and political equivalent of the rule from when you were a kid, you and your siblings could fight and call each other names but you didn’t let people outside the family do that.

So it is, or is supposed to be, with politics.

But do those rules still apply if the international stage is on Canadian soil?

Justin Trudeau used an international summit, paid for by the taxpayers of Canada, to attack his political foes this week.

The Nature Champions Summit was held in Montreal over the past few days, here is how the government website described it.

“Nature champions from around the world, including governments, major philanthropists, business leaders, non-governmental organizations, youth, Indigenous leaders, and United Nations agencies will be coming together to build a new high-ambition coalition to drive global nature protection forward.”

So the Canadian government invited other countries, UN agencies and business leaders — plus movie star Harrison Ford — to Montreal to hear Trudeau launch partisan attacks on Andrew Scheer and Doug Ford?

That simply doesn’t seem right.

And make no mistake, the comments were overtly partisan and also completely false.

After speaking for a couple of minutes about the importance of climate change, Trudeau pivoted to launch the attack.

“The opposition denies that climate change is real,” Trudeau said.

“Look no further than Ontario to find a provincial government that is wasting taxpayers’ money fighting climate action in court, while ignoring their commitments to protect species at risk. It’s shortsighted and irresponsible and frankly, Canadians deserve better.”

Trudeau then made another false claim that the previous Conservative government did nothing to protect nature for 10 years.

Again, this is to an international gathering with governments and UN agencies present and Trudeau is treating it like a Liberal fundraiser where attacking the opposition is sport.

So let’s look at the claims, the false claims, that Trudeau made.

Does the opposition deny climate change?

Not at all.

Federal Conservative Leader Andrew Scheer may oppose Trudeau’s carbon tax plan but he has never said climate change isn’t real and has pledged to take a different approach.

Ontario Premier Doug Ford is the same. In fact, in the court challenge launched by his government, the opening arguments stated that the court battle was not over climate change but over the constitutionality of Trudeau’s approach.

Is the Ontario government ignoring species at risk?

They just announced that they will update the act and modernize it, they are taking a different approach than Trudeau but that doesn’t mean they are ignoring species at risk.

And as for the Conservatives doing nothing to protect nature for a decade, maybe Trudeau should look to the expansion of several national parks and establishment of new ones under the Harper government.

I expect politicians in this country to be tough on each other, to point out their differences, especially when asking for votes.

What I don’t expect is our PM to use an international gathering, paid for by taxpayers, to bash fellow Canadians with pure falsehoods as if it were just another Liberal campaign stop.

Trudeau is right about one thing, Canadians deserve better.

blilley@postmedia.com