It was often hard for Europeans to understand the Native American customs of trading. On encountering a native tribe, the Europeans would often be offered fur, food or other items as gifts. The Europeans would then feel no obligation to assist the natives against their enemies, which was the purpose of the gift-giving, from the native perspective. The Europeans never did catch on and were frequently viewed by the natives as welchers on the implied pledge of alliance they'd entered into by accepting the gifts.
After observing that Europeans were just as eager to trade with their enemies as themselves, the natives did eventually get the picture; but especially in New France, in Carolina, Virginia, and New England and in New Netherlands the Europeans became drawn into the endemic warfare of their trading partners.
After the United States became independent, trading with the Indianss or Native Americans was nominally regulated by the Trade and Intercourse Act of June 30, 1834. The Bureau of Indian Affairs issued licenses to trade in the Indian Territory, which in 1834 consisted of most of the United States west of the Mississippi River, where mountain men and traders from Mexico freely operated.
See also History of United States