The US Constitution authorizes the Legislativebranch (Congress) to regulate trade with foreign countries, between the states, and with Native American nations in Article I, Section 8, Clause 3.
The Legislative Branch
The National Government ( Congress) has the responsibility.
Congress is the legislative branch of the U.S. government. Its primary and most important responsibility is the creation of constitutional laws.
The judicial branch.
The primary responsibility of the executive branch of government is the enforcement of laws.
The judicial branch of government decides if the laws passed by the legislative branch are constitutional.
In the United States, the executive branch has the responsibility for enforcing laws.
In the U.S., the legislative branch of government is responsible, and has the constitutional powers, to declare war.