From 30 Philosophers, Chapter 24 on Locke, and Touchstone 60.

Due process is the procedural safeguard that stands between the individual and arbitrary exercise of authority. It is the legal structure that prevents your inherent rights from being unfairly stripped away. In essence, due process is the set of rules that ensures that if the government—or any other body—wishes to deprive you of your life, liberty, or property, it must do so following an established and predictable method.