The goal of the theory of separation of powers is to

The goal of the theory of separation of powers is to protect individual liberty by dividing the powers of government into three branches - legislative, executive, and judiciary - each with separate and distinct functions. This separation ensures that no one branch has too much power or authority, and that each branch serves as a check and balance on the others. By limiting the power of each branch and preventing any one branch from becoming too powerful, the separation of powers helps to safeguard against tyranny and ensure that the government is accountable to the people it serves.