One long term cause was the land problem; when the land was split the Natives could not go onto the traditional lands, e.g., the following of the Buffalos and sacred worshipping areas. It started confusion, because the Natives never thought that land could be owned. Soon there was to be a hate against the whites. A railway split the land; nobody could pass over the tracks from each side.
Another example of a long term cause was the railways and wagons trails. When th train was built, dividing the land, the Natives had to change certain traditions. They could not follow Buffalo, and to move onto land which previously used to be home or sacred. The Whites would shoot the Buffalo, only because they could, and thus weakening their “abilities” to survive without them. After the Whites had reduced the Buffalo population from several hundred thousands to only 200, the Native Americans could no longer survive to their fittest and had to surrender.
When disease struck, only the Whites could survive with their antibiotics. The Native American where not immune to such disease such as the common cold, which then wasn’t very common, had a great impact against the Natives. Many Natives would die against such pathetic diseases, which also reduced their numbers, which would lead to their war.
One short term cause was the Gold Rush. Because the land had been split into two, one for the Whites and one for the Natives, everything on one side belonged to each “civilization”. When gold was discovered on the Native Americans side, the whites who had originally created the rules or agreement for splitting the land in half discarded their plans and took off into their unopposed land. In reality when the Whites had discovered the gold, they “stole” it from the Natives and just left. This did have an effect to all the Natives Chiefs about whether they where allowed to cross into the “forbidden land”.
One last short term cause for the war the US Army and Government. The US Army was a scheme used for the protection of the whites when they went over to the other side of the “divided land” when they decided to kill buffalo or various other activities which weren’t allowed or wrong in the eyes of the Natives. When the US did, and when the Natives would rebel against it every now and then, they would attack like a war. This obstructed the agreement and changed everything. Now the Natives would rebel one final time.
The war did definitely start because of the whites, who had gone too far in abusing the land and rights. They would kill certain “Main” animals, destructing what ever they wanted, acting like that the land was theirs, not ever thinking about the causes, and if did, causes to eliminating the Natives.