A Washington Post columnist joked that after insulting most of its friends, it's about time the U.S. started a fight with Canada.

"I think after having insulted Australia, South Korea, Japan, Mexico and just about every one of our friends, it's about time that we hit Canada," Charles Krauthammer joked on a "Special Report" television panel on Fox News Tuesday.

"I still haven’t gotten over the War of 1812, so I have a personal animus here," he added.

Krauthammer was referring to U.S. President Donald Trump's announcement that there would be a tariff of up to 24 per cent on Canadian softwood lumber, and that duties will also be gathered retroactively.

"I still haven’t gotten over the War of 1812, so I have a personal animus here."

On Wednesday, The White House told U.S. media that it's weighing a plan to pull out of NAFTA, jolting both the Canadian dollar and the Mexican peso — a move that some trade experts viewed as a negotiating tactic.

"People don't realize Canada has been very rough on the United States," Trump said in a statement to press on Tuesday. "They've outsmarted our politicians for many years."