What gives the US president unilateral authority to impose tariffs?

Title pretty much says it all. I would really think congress would have a role in this but apparently they do not.

What part of the constitution and/or legislation grants the president authority to impose tariffs at his/her sole discretion?

Cliff-notes version:

FDR encouraged Congress to transfer authority on trade matters to him, and there there hasn’t been a legal challenge that has risen through the courts to say that they must own their Article 1 Section 8 responsibilities and are unable to abdicate those rights to the Executive branch.

Here is a more in-depth explanation.

This area isn’t my forte, but I believe some of the tariffs relate to this section of law.

To rat avatar’s point, courts have seen delegations of power from Congress to the Executive Branch to pass muster if there is an “intelligible principle” that guides how the Executive on how to exercise the powers. So, “The President can raise tariffs if the importation of things jeopardizes our national security” would probably be fine, but “The President is now in charge of all trade decisions” would not.

And indeed national security has been the legal excuse given in recent days.

Cannot Congress on its own accord take these rights back? … 2/3’s of each house would over-ride the presumed Presidential veto …

Undoubtedly so.

More interestingly, I am not certain the President can veto this. Well, one could obviously, but it might not have legal effect. While the current Executive-oriented law was passed by a duly processed bill and so on, and nominally could only be rescinded by a new enacted law, there may be a twist here. The power to set taxes, including tariffs, is inherent to Congress. While a President could veto a direct tax rate change, it’s arguable that Congress can, at any time through a majority vote, take back any powers it delegates. Those are, after all, Constitutionally embedded rights and courts may well side with Congress if there was a dispute.

It would be an intersting case, in any event.

I don’t see how this follows. If the power was delegated by statute, it can only be undelegated by a new statute. And passing a statute necessarily involves the possibility of a presidential veto.

Yeah, the President has a right to veto “Every Bill” and “Every Order, Resolution, or Vote to which the Concurrence of the Senate and House of Representatives may be necessary (except on a question of Adjournment).”

That’s not quite true. There’s one thing the president isn’t required to approve and that’s constitutional amendments. Of course the supermajority needed for those is the same as overriding a veto: 2/3 vote in each house.

Two things: constitutional amendments and impeachment of the President. The latter requires only a simple majority of the House of Representatives, and the President doesn’t approve it and can’t veto it. Although technically that’s not something that requires “Concurrence of the Senate and House of Representatives”, just the House.