The Constitution limits presidential power thanks to the system of checks and balances.
Within the US Constitution, each branch of the federal government is given specific powers. The executive branch, which consists of the presidency, enforces laws. The president also has the ability to pass certain laws without Congressional approval. This is known as an executive order. However, the presidents power is not absolute, as his/her actions can be undone by another branch of the federal government.
For example, the Supreme Court can rule an executive order unconstitutional if they feel it violates the rights of citizens. This ensures that the president cannot make any law they want.