What is the primary function of the Constitution?

The primary function of the Constitution is to set up the government and protect Americans' rights. This foundational document outlines the structure of the federal government, delineating the roles and powers of the three branches: legislative, executive, and judicial. By establishing a system of checks and balances, the Constitution ensures that no one branch becomes too powerful.

Moreover, the Constitution includes the Bill of Rights, which enumerates specific protections for individual liberties and rights. These rights are essential in safeguarding citizens from potential government overreach, thus affirming the Constitution's role in protecting Americans' rights.

In contrast, the other options do not encapsulate the central purpose of the Constitution. Ending all wars is an ambitious goal that extends beyond the scope of governance and individual rights. While creating state laws is a function of state constitutions and legislatures, it isn’t the primary purpose of the U.S. Constitution itself. Establishing military rules falls under the domain of legislation and executive power rather than being a primary purpose of the Constitution. Hence, choice B accurately reflects the main objective of the Constitution in setting up the framework of U.S. governance while ensuring the protection of individual rights.