The cause of the Indian wars in the Pacific Northwest were mainly caused by broken treaties, which led to many deaths and Indians being forced into small reservations

True

Explanation:

It is TRUE that the cause of the Indian wars in the Pacific Northwest was mainly caused by broken treaties, which led to many deaths and Indians being forced into small reservations.

This is evident in the fact that the American government in their bid to use the land occupied by the native Americans in the Pacific Northwest of the United States or even any other area in the region, ask the native Americans to move to a new reservation with a promise of no trespassing on their lands or reservation.

However, many times, the US government tends to break this treaty, and war always eventually occurred as a result.