權力分立
Secondly, the idea of separation of powers is another theory about how a democratic society's government should be organized. In contrast to legislative supremacy, the idea of separation of powers was first introduced by Montesquieu; it was later institutionalized in the United States by the Supreme Court ruling in "Marbury v. Madison" under the court of John Marshall. Separation of powers is based on the idea that no branch of government should be able to exert power over any other branch without due process of law; each branch of government should have a check on the powers of the other branches of government, thus creating a regulative balance among all branches of government. The key to this idea is checks and balances. In the United States, judicial review is considered a key check on the powers of the other two branches of government by the judiciary.