Article I, Section 8 of Constitution lists 27 expressed powers of Congress
Include power to declare war, levy taxes, regulate commerce and currency
The 27 expressed powers of Congress listed in Article I, Section 8 of the Constitution grant the legislative branch a huge amount of authority over American national policy, both foreign and domestic.
The most important powers include the power to tax, to borrow money, to regulate commerce and currency, to declare war, and to raise armies and maintain the navy. These powers give Congress the authority to set policy on the most basic matters of war and peace.
Congress's other expressed powers are wide-ranging, including:
The power to establish rules to allow foreign-born immigrants to become citizens of the United States
The power to make rules for bankruptcies
The power to punish counterfeiters
The power to set up a national post office
The power to provide for copyrights and patents to protect the work of inventors and artists
The power to organize all federal courts below the Supreme Court
The power to punish pirates
The power to hire pirates to attack foreign enemies
The power to make rules to regulate the conduct of the armed forces
The power to call out the militia to defend the country from invasions or insurrections
The power to organize and discipline the militia
The power to govern the federal capital (Washington, DC)
The power to acquire lands from the states for use by the federal government
And, last but definitely not least:
The power to "make all Laws which shall be necessary and proper for carrying into Execution the foregoing powers...."