Answer:
Fur trade
Pioneer settlers were sometimes pulled west because they wanted to make a better living. Others received letters from friends or family members who had moved west. These letters often told about a good life on the frontier. The biggest factor that pulled pioneers west was the opportunity to buy land.
Originally Spain, Great Britain, Russia, and the United States claimed the territory. In 1819, under terms of the Transcontinental Treaty, Spain ceded its claims to the territory to the United States.
Infectious diseases and colonization.
Sorry, I don't have an answer more specifc than that.
If someone where to set aside the check of the "Executive Branch". The president would have alot of power and no one could stop him because he has so much authority.
Hope this helps
-Jurgen :D
