After back-and-forth tariff threats that sent markets sharply lower Tuesday, the US commerce secretary and the premier of Ontario said they would meet Thursday to renegotiate the free trade treaty known as the USMCA.

Canada's retaliatory tariffs as a permanent policy tool are economically counterproductive and may slow the implementation of climate initiatives.

The U.S. president ratcheted up a trade war with America's northern neighbor after Ontario's surcharge on electricity sold to the United States.