1. Treaties and Historical Alliances: Many American Indian tribes had existing treaties with the federal government or individual states that determined their rights, territories, and relationships. Some tribes, particularly in the West and Southwest, had stronger ties to the Union government, while others in the South had closer connections to Confederate states.
2. Tribal Autonomy and Sovereignty: Many tribes saw the Civil War as an opportunity to assert their sovereignty and resist encroachment on their lands. Some tribes allied with the side they believed would respect their autonomy, while others aimed to play one side against the other to maintain their independence.
3. Influence of Confederate Policies: The Confederate government offered some American Indian tribes the promise of self-government, land rights, and protection against encroachment. This attracted certain tribes, particularly in the South, to support the Confederacy.
4. Union Military Presence: In some regions, American Indians sided with the Union because of the presence of federal troops and forts, which often provided protection against hostile settlers or neighboring tribes.
5. Cultural and Economic Ties: Factors such as trade relationships, cultural similarities, and prior military engagements with either the Union or the Confederacy also influenced the decisions of some tribes.
6. Forced Removal and Past Conflicts: Some tribes had experienced conflict or forced removal from their ancestral lands by the U.S. government in the past. These experiences could shape their attitudes toward the Union and influence their choices during the Civil War.
7. Internal Disagreements: Not all members of a tribe necessarily agreed on which side to support. Some tribes experienced internal conflicts and divisions over whether to align with the Union or the Confederacy.
It's important to note that the allegiances of American Indian tribes were not uniform, and various groups made different decisions based on their specific circumstances and histories. Some tribes remained neutral, while others actively participated in the conflict on either side.