Since the 1970s, federal American Indian policy in the United States has been aimed at promoting self-determination through self-governance by federallyrecognized tribes. This policy has proven to be the only policy that has worked to make significant progress in reversing otherwise distressed social, cultural and economic conditions in Native communities. The policy of selfdetermination reflects a political equilibrium which has held for four decades and which has withstood various shifts in the party control of Congress and the White House. While Republicans have provided relatively weak support for social spending on Indian issues when compared to Democrats, both parties’ representatives have generally been supportive of self-determination and local self-rule for tribes. Analysis of thousands of sponsorships of federal legislation over 1970-present, however, finds the equilibrium under challenge. In particular, since the late 1990s, Republican congressional support for policies of self-determination has fallen off sharply and has not returned. This calls into question the sustainability of self-determination through selfgovernance as a central principle of federal Indian policy.