How did europe and natives form alliances when conflict with one another?

In 17th and 18th Centuries, both America and Europe were in relative conflict. The European powers,Spain, Britain and France, were often at war, particularly due to territorial control and expansion of their colonies. In America, native tribes would have a similar situation, which became worse once the settlers arrived.

Each European power would find an allied tribe, because each party would be following its own interest as it happened with the fur trade in which the Dutch, the French  and the British shared a common interest. In this case, the French were allied with the tribe of the Hurons, and the Dutch and later the English with the powerful Iroquis, a tribe composed by initially 5 and later 6 native nations. All the European powers provided arms to the natives and they fought other tribes as well, for example,the Iroquis attacked the Hurons and they had to flee, arriving to other areas starting a new conflict with the local tribes.

As a conclusion, the European formed alliances with the natives based on shared interests for expansion,control of resources and land, and they used the conflicts, already arosen, to seal this alliances and fight their counterparts.

it was certainly a debatable decision, mainly because it was based primarily on political - and not on legal or social - views. since the congress at that time was led by members of the republican party, and the territory that the tribes wanted to turn into an exclusively indian state was predominantly democratic, the proposal (as expressed in the constitution) did not succeed, but the constitution itself proved to be of crucial importance in the creation of the state of oklahoma, and, most importantly, it guaranteed the involvement of representatives of the indian tribes in the government of the future joint state.  

as a member of congress, i would have voted to ratify the constitution, or at least to have it tabled. ignoring it was an interested and partial decision.