What did the Kentucky and Virginia Resolutions claim that states had the right to do?

The resolutions argued that the states had the right and the duty to declare unconstitutional those acts of Congress that the Constitution did not authorize. ... The Kentucky Resolution of 1799 added that when the states determine that a law is unconstitutional, nullification by the states is the proper remedy.

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.