What is the purpose of a constitution?

The purpose of a constitution is primarily to establish a plan of government. It serves as the foundational legal framework for how a nation or organization is governed, outlining the structure and powers of different branches of government, the rights of citizens, and the processes for enacting laws and policies. By setting up this framework, a constitution ensures that there is a clear understanding of the roles and responsibilities of those in power, as well as the rights and duties of the citizens, thus promoting order, stability, and justice within society.

In contrast, the other options do not capture the comprehensive function of a constitution. While a national anthem is an important symbol of national identity, it does not pertain to governance. The determination of tax rates and the regulation of commerce are specific functions that may fall under the authority of government established by a constitution, but they are not the overarching purpose of the constitution itself.