The correct answer is there was continual violent conflict as the US government forced Native Americans off their land.
The United States had multiple violent conflicts against Native Americans including the Battle of Little Big Horn and the Battle of Wounded Knee.
The Battle of Little Big Horn resulted from US encroachment on Native American reservation land due to the discovery of gold. The US troops, lead by General Custer, lost this battle. This was an embarassing loss by the US troops, one in which they would try to avenge throughout the late 19th century.
The Battle of Wounded Knee would be another example. US troops misinterpreted the meaning of the Ghost Dance done by Native Americans. Troops saw it as a preparation for war rather than what it really was, a religious revival movement. This caused tension between the two and eventually lead to conflict in which anywhere from 150-300 Native Americans were killed by US troops.
