checks and balances,

1. Separation of Powers
The Constitution establishes a system of separation of powers among the three
branches of government.
The framers of the Constitution derived their ideas about the separation of powers from
the French philosopher Montesquieu, and they divided the U.S. government into the
legislative, executive, and judicial branches.
Article I gives Congress the power to make the laws.
Article II gives the president the power to enforce the laws.
Article III gives the judiciary the power to interpret the laws.

2. Checks and Balances
The framers did not make the boundaries between those branches absolute. Instead,
they created a system of checks and balances in which each branch exercised some
restraint on the power of the other. For instance;
Congress has the power to pass laws, but the president can veto those laws.
The president can make treaties, but the Senate must approve them.
Judges have life tenure to give them independence, but the president and the Senate
together select judges.
James Madison described the principle of checks and balances in Federalist 51:
“Ambition must be made to counter ambition. The interest of the man must be connected
with the constitutional rights of the place.”