Article II of the U.S. Constitution states that “The executive power shall be vested in a President of the United States of America.” As the ultimate executive authority, the President serves as commander in chief of the United States military, has the power (“with the advice and consent of the Senate”) to make treaties and appoint judges and civil servants. The President also executes and enforces the laws of the United States and runs the day-to-day affairs of the government. Additionally, every President takes an oath to “preserve, protect, and defend” the U.S. Constitution.
www.justicelearning.org, The United States Constitution, what it says, what it means, A Hip Pocket Guide (Oxford University Press)