(Article I, Section 8)The Congress shall have power...(t)o regulate commerce with foreign nations, and among the several states, and with the Indian tribes....
(perhaps the most-abused and -misunderstood clause of the Constitution)(t)o make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this Constitution in the government of the United States, or in any department or officer thereof.
The line of reasoning is that since virtually all of the commerce that takes place at a dock is with a foreign nation, Congress would have a role in this. The scope of this role would then fall into debate (IMHO, the further the claws of government remain from this, the better).
Not even close to being true.
The media can fly a helicopter over the ocean and show ships waiting to be unloaded but they can't get photos of loaded containers in Phoenix or Salt Lake held up because there is no room in the port for storing all the outbound cargo containers. Inland export shippers rely on the ports of coastal states to load their cargo on the vessels.
There will be no mention of lost wages in Arizona or Missouri resulting from production stoppage in inland states. The international commerce is always interstate commerce.