What primarily motivated Native American nations to engage in conflicts with the expanding U.S. government?

The motivation for Native American nations to engage in conflicts with the expanding U.S. government largely stemmed from the need to protect their resources. As the U.S. government expanded westward, it encroached upon the lands traditionally held by various Native American tribes. These lands were not just territories; they were rich in resources that were vital for the survival and culture of these communities, such as hunting grounds, rivers for fishing, and areas for agriculture. The intrusions led to a direct threat to their way of life, prompting Native American nations to resist and fight to preserve their lands and resources.

Engaging in armed conflict was often seen as necessary to defend their sovereignty, support their communities, and maintain access to the natural resources that were integral to their livelihoods. This defensive stance against encroachment was, therefore, a fundamental factor that motivated many Native American nations to confront the U.S. government's expansionist policies.