Earlier quoted context omitted.
The President can only legally set tarrifs in an "emergency". Planning tarrifs 90 days out is really stretching the definition--I'm not holding my breath, but maybe the courts will uphold the constitution on this one?
Normally there are rules regarding how long an emergency can last. This is why, I kid you not, the Republican controlled Congress declared there are no more calendar days in this session of Congress. Every day is March 11. So they'll let him do it as long as he likes.
This is also how this shambling ghoul gets what any actual citizen of earth would consider a third term. It's already done! This is why he said "you'll won't have to vote again."
The president is only 50 days into his term forever; time is stopped. Hell upon us eternal.