Sort of. Campaigning on vague slogans about something doesn't mean you have democratic legitimacy to avoid the whole process by which that something is supposed to get turned into law.

Congress has previously delegated tariff authority for emergencies to allow the president to do stuff like impose (temporary) sanctions in fast moving foreign policy negotiations. The mechanism by which all the current tariff stuff is getting done is by Trump having declared that trade deficits (in goods only), by virtue of existing, constitute such an emergency, despite having been observed for 80 years and being both an inevitable consequence of the US being an advanced country. Like, the whole thing rests on a total perversion of the law's intent, economics, and the English language itself.