what is the purpose of the constitution
3. Protection of Personal Liberty. The third main purpose of the Constitution is to protect the personal liberty of citizens from intrusions by the government. A few of these protections are found in the main body of the Constitution itself.he Constitution has three main functions. First it creates a national government consisting of a legislative, an executive, and a judicial branch, with a system of checks and balances among the three branches. Second, it divides power between the federal government and the states.