Politico reports:

Though no final decisions have been made, Trump could start, as early as Day 1 of his term, to impose tariffs through executive action under the International Emergency Economic Powers Act, a law that gives the president broad authority to take trade actions. Other tariff actions Trump is expected to take are being explored under laws he used during his first term to impose duties on China and other countries. Those latter options would require months of investigation by federal agencies, people close to Lighthizer caution, and the exact sequencing of actions is still being discussed.

Vox reported earlier this week thatTrump's proposed tariff policy "alone could raise consumer prices by as much as 5.1 percent and could diminish US economic growth by up to 1.4 percent," according to The Budget Lab at Yale.

Still, Vox notes that "the legal arguments in favor of allowing Trump to unilaterally impose high tariffs are surprisingly strong. Several federal laws give the president exceedingly broad power to impose tariffs, and the limits imposed by these statutes are quite vague."