The topic of discussion for this Constitution Monday comes from Article I.8.3: "The Congress shall have Power to … To regulate Commerce with … the Indian Tribes." This provision in the U.S. Constitution gives Congress the power to regulate trade with Indian tribes.
At the time that the Constitution was written and ratified, the U.S. Governments treated Indian tribes as sovereign nations similar to the nations of Europe. The government used treaties with the Indian nations just as they did with other nations even though they thought that the Indians would eventually become an assimilated into the culture of the new nation.
Over a period of many years the government established the Bureau of Indian Affairs (1824 - to deal with any problems involving Indians), passed the Indian Removal Act (1830 - to open up lands west of the Mississippi River in order to have places to relocate the tribes), made the Bureau of Indian Affairs a branch within the Department of the Interior (1849), stopped considering Indian tribes as independent or foreign nations by congressional act (1871), imposed a system of criminal laws for Indians living on reservations (1886), and granted U.S. citizenship to all Indians born within the borders of the United States (1924). The sale of alcohol to Indians was about the only regulated commercial activity with Indian tribes for many years, but their gambling casinos may now come under the commerce clause.
Ideas and quotes are from W. Cleon Skousen, The Making of America: The Substance and Meaning of the Constitution, pp. 410-411.