Because the states wrote and ratified the Constitution that way. Congress did not create itself.
Congress
the legislative branch
Congress held the power in the national government*There are three branches of government. They are legislative, executive, and judicial. The Articles of Confederation only had a legislative branch. Because of this fact, Congress held the power in the national government.I hope this helped! :)
The Legislative Branch (Congress) has the power to declare war.
In a federal system, the state and national governments share power. Some authority is exclusive to the national government and some is reserved to the states and the people, but other powers (such as the right to tax) are concurrent, or shared by both entities.
The legislative branch lays and collects taxes. They have what is called the power of the purse. They control everything that involves federal money.
Approve Presidentail nominations
An example of Congress having too much power is the fact that they can impeach even the president. The Congress is the part of the legislative branch of government.
Congress which is a part of the Legislative Branch of the government, checks the president and the executive branch to keep them from overstepping their power.
Congress is vested with the power to make all laws.
Legislative Branch i.e. Congress
Both the Legislative (Congress) and the Judicial (Supreme Court), have the power to keep the President's power in check.