Does a tariff require congressional approval? Is there any way the executive branch alone can institute one?

Answer 1

Article 1/Section 8 of the Constitution explicitly grants tariff policy to Congress. The president may propose shifts, but only Congress can authorize it.

Answer 2

The purse string of our nation are and always have been in the hands of the Legislative branch by design. You can't give the Executive branch complete control to insure there can be no dictator. The Judicial branch insures any bill that is passed is Constitutional. The Executive branch can request tariffs and tax increases or cuts, but the Legislative branch must authorize it.