In regards to the statutory law.
The King's position is that a national emergency is whatever he says it is, and that it then gives him unlimited power to violate other laws. That is palpably stupid.
After the National Emergency act of 1976, designed expressly to limit Presidential abuse of national emergencies, the IEEPA was passed in 1977. Unlike the act in 1976 in 1977 he IEEPA further specified "that the President may only use powers it authorizes to deal with an “unusual and extraordinary threat, which has its source in whole or substantial part outside the United States, to the national security, foreign policy, or economy of the United States, if the President declares a national emergency with respect to such threat.”136 The statute further provides, somewhat ambiguously, that the President may only use IEEPA powers activated by a declaration of national emergency to “deal with” that specific emergency.13"
In other words, the later statue imposes a limitation that it be a true emergency, something unusual and extraordinary threat to the economy, and among its powers it does not specify that Congress is transferring its Constitutional power to impose mass taxes on US citizens.
Therefore there is only one of two possibilities:
a) Trump is clearly exceeding his authority as trade deficits, Brazil's treatment of its President, and numerous other excuses Trump has given comes within a country mile of meeting that criteria. OR
b) If, on the other hand, one hopes to defend King Trump on the presumption that the IEEPA wording is unclear and leaves room to ignore the criteria as too ambiguous then the President's actions are a violation of the Major Questions doctrine, as recently established by the Courts rejection of deference to an executive agency:
"
The Major Questions Doctrine, introduced by the Supreme Court in the Chevron decision, requires agencies to point to clear congressional authorization for transformative regulatory initiatives. This doctrine shifts the burden of proof from the courts to the agencies, which must justify their interpretive actions not directly authorized by Congress. The "elephants in mouseholes" metaphor from Justice Antonin Scalia's opinion in Whitman v. American Trucking Ass'ns (2001) illustrates this shift, suggesting that Congress does not "hide elephants in mouseholes" when granting massive power. "
If Congress did not provide clear Congressional authorization for this transformative tax and tariff initiative, then the executive actions are moot. The granting of massive power to the executive requires the administration to point to clear congressional authorization.
Hence, if the courts are not bending to politics, the mass tariffing is not authorized.