When the proper court determines that a legislative act (a law) conflicts with the constitution, it finds that law unconstitutional and declares it void in whole or in part. This is called judicial review. ... Thus, national constitutions typically apply only to government actions.
The Framers of the Constitution gave the President the power to veto acts of Congress to prevent the legislative branch from becoming too powerful. This is an illustration of the separation of powers integral to the U.S. Constitution
France transferred the Louisiana Territory to "Spain" after the French and Indian War, although it should be noted that not all of the territory went to Spain, with some of it initially going to England.
