A legal doctrine that, among other things, generally prevents states from enforcing their laws against Native American tribes to thwart these state actions, TUCKER devised a scheme to claim that his lending businesses were protected by sovereign immunity. Starting in 2003, TUCKER joined into agreements with a few indigenous American tribes (the “Tribes”), such as the Santee Sioux Tribe of Nebraska, the Miami Tribe of Oklahoma, together with Modoc Tribe of Oklahoma.