Tariffs are put on at the federal level, not the provincial level, but your misunderstanding is very common.

The US themselves are tariffing potash at 25% from Canada coming into the US.

In Canada

> Section 91(2) of the Constitution Act, 1867 gives Parliament exclusive jurisdiction over “the regulation of trade and commerce.”

However Trudeau has repeatedly emphasized working closely with the Premiers to ensure that tariffs aren't discriminatory against some provinces and favouring others. It seems to imply that despite his legal power, the federal government would not impose those tariffs as it would come at the cost of Canadian unity.

The province of Ontario is in the headline of this article.

Ah, I see our disconnect. You are talking about export taxes and I am talking about the federal government.

You still might be right. Ontario might be able to adjust electricity export prices because it's a highly regulated provincially regulated market. Alberta might not be able to unilaterally add an "export tax" to oil the same way.

OTOH, if Alberta asked for one, the federal government would comply.

And that looks like it applies here as well. Today's announcement was a joint announcement between the provincial and federal government.

Not anymore. Conservatives in Western Canada are just as anti-Trump as Liberals now.