Say the Sioux are able to capture Fort Ridgely, New Ulm and defeat Sibley's relief forces. Could this have had any effects on the American Civil War, if the local Minnesota troops couldn't handle the situation?
Would the Sioux be able to capitalize on these victories and force U.S. to grant them a larger reservation?
How would this impact the later wars between the U.S. and Sioux: Red Clouds War and the Great Sioux War?