The nonintercourse act caught my eye :-)

The Nonintercourse Act (also known as the Indian Intercourse Act or the Indian Nonintercourse Act) is the collective name given to six statutes passed by the United States Congress in 1790, 1793, 1796, 1799, 1802, and 1834. The Act regulates commerce between Native Americans and non-Indians. The most notable provisions of the Act regulate the inalienability of aboriginal title in the United States, a continuing source of litigation for almost 200 years. The prohibition on purchases of Indian lands without the approval of the federal government has its origins in the Royal Proclamation of 1763 and the Confederation Congress Proclamation of 1783.