What foundational role did the US Constitution establish for the American government?

The US Constitution plays a foundational role in defining the relationship between the people and the government by establishing principles such as popular sovereignty, which asserts that the authority of the government is derived from the consent of the governed. Through the Constitution, individual rights are protected, and a framework for federalism is created, delineating the powers of the federal government, as well as those retained by the states. It emphasizes the idea that the government exists to serve the citizens and must operate within the boundaries set by the Constitution itself.

The other options, while relevant aspects of government function, do not capture the holistic and foundational nature of the relationship established by the Constitution. For example, limiting the powers of state governments is an important aspect but is more a result of the Constitution than its foundational role. Similarly, establishing processes for enacting laws or creating a system of direct democracy does not encapsulate the broader relationship defined between citizens and their government. Therefore, defining this relationship underscores the Constitution's vital role in shaping American governance.