There are many expressed or enumerated powers that the United States Constitution establishes for Congress.
Article One of the Constitution addresses the legislative branch of government. The framers had specific designs for what each branch of government could do. They wanted to ensure clear communication and the ability to use governmental power properly.
In section eight, the first enumerated power regards taxation. Congress has the
"power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defense and general welfare of the United States; but all duties, imposts and excises shall be uniform throughout the United States."
It makes sense that this is the first stated Congressional power. Unfair taxation was one of the reasons why the colonists fought Britain in the American Revolution. The framers, many of whom fought as colonial patriots against the British, did not want to experience the same abuse. By having Congress control taxation, they figured power would be less likely to be abused if it was shared amongst more than 500 people, rather than placed in the hands of one president.
There are many other powers that the Constitution explicitly grants to Congress. However, I think that one of the most important would be "To declare war, grant letters of marque and reprisal, and make rules concerning captures on land and water." The president is the Commander in Chief, but the nation can only enter war with Congressional approval. The Framers were quite insightful in understanding that one of the best ways to limit the machinery of war was to mandate its approval through the legislature. Once again, the desire to disperse power amongst more people becomes evident in the legislative branch's expressed power to declare war.
There are actually 27 expressed powers of Congress according to the Constitution, Article I, Section 8. In our system of government the checks and balances provided by the three branches (Legislative, Judicial, and Executive) rest on the various branches using their powers accurately and conscientiously.
One of the expressed powers of Congress is the power to declare war. Because war is such an extreme and serious step taken on the world stage, it needs to be engaged in only after thoughtful, serious debate by the representatives of people of the United States of America. Our government is "of the people, by the people, and for the people," therefore only the legislative branch with its inherent accountability to the people is given this right.
Another of the expressed powers is to levy taxes. In order for government to work it must have funds. Without the power to levy taxes and provide an income for the government, it would cease to exist. This, too, is controlled by the body of government that most closely answers to the public (and for a good reason).
In Article I, Section 8 of the U.S. Constitution there are several enumerated powers that were established to help limit the power of the new Congress. Some of these powers include: pay debts and borrow money, declare war, coin money, and regulate commerce. At the very end of the list there is the power to make all laws "necessary and proper" to carry out the enumerated powers. This is also called the Elastic Clause. This clause is extremely important, because it allows Congress to expand its enumerated powers if needed. In the Supreme Court case of McCulloch v. Maryland (1819), the Supreme Court ruled that Congress had the power to establish a national bank, which would collect taxes, borrow money, and pay debts. Congress was able to establish the bank, because of the Necessary and Proper Clause.
Congress has both expressed and implied powers as well as non-legislative powers. The expressed powers of Congress are written in Article 1 of the United States Constitution. Two expressed powers that Congress has are the power to tax and the power to regulate commerce. The power to tax is the power to collect money for use by the government. This can be done through direct taxes and indirect taxes. The federal income tax is an example of Congress's exercise of its power to tax. Additionally, Congress has the power to regulate both foreign and interstate commerce. One way that Congress does this is through the use of the Interstate Commerce Clause. Other expressed powers of Congress include: the power to coin money, the power to borrow money, the power to declare war, and more.