One thing the doctrine of "separation of powers" is designed to prevent:

Question

States from challenging federal laws
The President from abusing executive authority
Congress from interfering with the judiciary

Answer 1

The doctrine of "separation of powers" is primarily designed to prevent the President from abusing executive authority. This doctrine divides government responsibilities into distinct branches (typically the executive, legislative, and judicial branches) to ensure that no one branch becomes too powerful and that each branch can check the other, thereby maintaining a balance of power.