U.S. tariffs on Canada have put experts at odds over how appropriate the action was, particularly given the unaddressed demand side of the fentanyl epidemic.

U.S. President Donald Trump's increased tariffs on steel and aluminum imports took effect on Wednesday as prior exemptions, duty free quotas and product exclusions expired, as his campaign to reorder global trade norms in favor of the U.

Trump previously said he would increase from 25% to 50% tariffs for Canada after Ontario said it would raise electricity prices on U.S.