One of the foreign affairs powers of congress allows it to control

Foreign commerce

Such power is part of the enumerated powers of the Congress which is outlined in Section 8, of the article I of the U.S. Constitution, it states the following:

The Congress shall have power (...) to regulate commerce with foreign nations, and among the several states, and with the Indian tribes

This means that one of the Congress' duties is to control the sale, marketing, trade, and traffic of goods or commodities between the United States and other nations.

The Constitution of the United States is the foundation of our Federal Government. It is often called the supreme law of the land; no law may be passed that contradicts its principles. At the same time, it is flexible and allows for changes in the Government. The Constitution is known as a “living” document because it can be amended, although in over 200 years there have only been 27 amendments.

The Constitution is organized into three parts. The first part, the Preamble, describes the purpose of the document and the Federal Government. The second part, the seven Articles, establishes how the Government is structured and how the Constitution can be changed. The third part, the Amendments, lists changes to the Constitution; the first 10 are called the Bill of Rights.

The Constitution established a Federal democratic republic. It is the system of the Federal Government; it is democratic because the people govern themselves; and it is a republic because the Government’s power is derived from its people.

The purpose of our Federal Government, as found in the Preamble of the Constitution, is to "establish Justice, insure domestic Tranquility, provide for the common defense, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our posterity." The Founding Fathers established three main principles on which our Government is based:

Inherent rights, or rights that anyone living in America has

Self-government, or Government by the people

Separation of powers, or branches of Government with separate powers

After the American Revolutionary War (1775-1783), the states were functioning under the Articles of Confederation, but the Articles provided little guidance to the states. In September of 1786, there was a meeting in Annapolis, Maryland, where representatives from New York, New Jersey, Delaware, Virginia, and Pennsylvania met to see what they could do about trade barriers set up among the states. The system of government set up by the Articles of Confederation did not regulate trade among states and needed to be changed.

hope I helped you ;)