What exactly is the situation with the United States imposing a 10% aluminum tariff on Canada?

U.S. President Trump announced on Thursday that he would re-impose a 10% tariff on Canadian aluminum. This comes just over a month after the new United States-Mexico-Canada Agreement came into effect, an agreement aimed at reducing trade barriers in North America.

“Earlier today I signed a proclamation which will re-impose tariffs on Canadian aluminum to protect American industry,” U.S. President Trump said in a speech at a Whirlpool plant in Ohio. “As always, Canada is taking advantage of us ... This is very unfair to our jobs and aluminum workers.”

Trump's decision was criticized by business groups. Myron Brilliant, executive vice president and head of international affairs at the U.S. Chamber of Commerce, said the tariffs would not only raise costs for U.S. manufacturers, which are opposed by most U.S. aluminum producers, but would also invite retaliatory actions against U.S. exports, as has happened before. “We urge the government to reconsider this move,” he said.

The Trump administration first imposed tariffs on steel and aluminum in March 2018, arguing that imported steel and aluminum threatened U.S. national security. Tariffs eventually took effect on steel and aluminum imports from nearly every country in the world.

This has also become a source of tension between the United States and Canada as they renegotiate the North American Free Trade Agreement. The Canadian government has argued that importing metals from Canada does not pose a threat to U.S. national security because of the two countries' long-standing alliance.

But it wasn't until May 2019 that the United States agreed to lift its steel and aluminum tariffs on Canada. Because Republican lawmakers told the White House that if this was not done, the new USMCA would not be passed by Congress.