Trump imposes tariffs arbitrarily to punish countries he does not like. There is no vigorous examination, hearings, and debate.Tariffs have their place.
Such as when a country uses it's national government to assist an industry, so they can produce goods at less than the market rate of other countries.
Tariffs are for "unfair" competition.
And to protect a countries infant industries.
That is why the legislative body imposes them after vigorous examination, hearings and debate