President Trump announced today that he has ordered an increase in tariffs on Canadian steel and aluminum, raising them from 25% to 50%, in response to Ontario Premier Doug Ford’s recent imposition of a tax on electricity exports to the United States.

“Based on Ontario, Canada, placing a 25% tariff on ‘electricity’ coming into the United States, I have instructed my Secretary of Commerce to add an ADDITIONAL 25% tariff, to 50%, on all STEEL and ALUMINUM COMING INTO THE UNITED STATES FROM CANADA, ONE OF THE HIGHEST TARIFFING NATIONS ANYWHERE IN THE WORLD. This will go into effect TOMORROW MORNING, March 12th,” President Trump announced on Truth Social.

Premier Ford’s electricity tax was enacted as a retaliatory measure against the U.S. administration’s previously announced tariffs on foreign steel and aluminum, which are set to take effect at 12:01 a.m. on March 12. In addition, Ford has threatened to cut power exports to the U.S. amid his re-election campaign in Toronto and has halted shipments of nickel—a key industrial metal—produced in Ontario.

More details on Ford’s actions can be found here.

While Ontario does send electricity to parts of the U.S., a big chunk of America’s nuclear energy actually depends on uranium from Saskatchewan. Lastly, President Trump mentioned that he’s getting ready to declare a “National Emergency on Electricity” in areas like Minnesota, Michigan, and New York, which rely on Ontario for power. On top of that, his administration is pushing Canada to drop its tariffs on U.S. agricultural imports.