On June 2, 1924, President Calvin Coolidge signed into law the Indian Citizenship Act (ICA), which unilaterally made United States citizens of all indigenous people living in the United States. This new law made citizens of approximately 125,000 of the 300,000 indigenous people in the country (the remainder were already U.S. citizens). Usually, people who have been excluded from American political life see the codi- fication of their citizenship status as an unambiguously positive political development. In the case of indigenous people and U.S. citizenship, however, one cannot find such clear and certain statements. All indigenous people certainly did not look at U.S. citizenship in the same light; in fact, very few saw it as unambiguously positive. This study demonstrates that the indigenous people who engaged the debate over U.S. citizenship came to define themselves, in various ways, as “ambivalent Americans,” neither fully inside nor fully outside the political, legal, and cultural boundaries of the United States. This effort to define a form of ambivalent American-ness reflects a significant tradition in indigenous politics, which involves indigenous political actors working back and forth across the boundaries of American political life to secure rights, resources, and/or sovereignty for the indigenous people they represent.