What is the principal function of a written constitution?

The principal function of a written constitution is to outline the structure and powers of a government. A constitution serves as the fundamental legal document that provides the framework for governance, detailing how power is divided among different branches of government, such as the executive, legislative, and judicial branches. It establishes the principles by which government operates, sets limits on governmental authority, and ensures a system of checks and balances to prevent any one branch from becoming too powerful.

By clearly delineating the roles and responsibilities of various government entities, a written constitution also serves to protect individual rights and liberties by providing a legal basis for the enforcement of such rights. While establishing laws for individual conduct, granting citizenship rights, and regulating trade and commerce may be important functions within a society, they are generally derived from or operate within the broader framework established by the constitution. Therefore, the central role of a written constitution is to define and outline the organization and power dynamics of government itself.