How does a classical liberal system protect the rights of citizens?

In a classical liberal system of governance, the rights of citizens are protected in two fundamental ways. Most largely, it views the basic relationship of government and governed as consensual: government exists and acts only by consent of the governed. Additionally, and in numerous particular ways, it limits the privileges and powers of governing agencies, bodies, and officials, whether in terms of scope, time-limits, internal checks and balances, or other limitations.