Final answer:
Former President Franklin D. Roosevelt used the Constitutional Principle of Checks and Balances when exercising his veto power.
Step-by-step explanation:
Former President Franklin D. Roosevelt exercised the Constitutional Principle of Checks and Balances when he vetoed 635 bills during his presidency. This principle is a fundamental aspect of the United States government that ensures no one branch has too much power. The power to veto legislation allows the President to check and balance the powers of the legislative branch, ensuring that laws align with the President's vision and priorities.
Learn more about Constitutional Principle of Checks and Balances