What significant principle was established by the Kentucky and Virginia Resolutions?

The Kentucky and Virginia Resolutions established the principle that states have the right to nullify federal laws they believe to be unconstitutional. This was a response to the Alien and Sedition Acts of 1798, which many viewed as overreach by the federal government. Thomas Jefferson and James Madison drafted these resolutions to assert that states could refuse to enforce these federal laws within their borders, arguing that the federal government was created by the states and thus should be constrained by them. This significant principle of nullification underscored a tension between federal authority and states' rights, a recurring theme in American political discourse. The resolutions laid the groundwork for debates about the balance of power between national and state governments that would continue throughout U.S. history.