The term "Indian country" is a legal term that evolved out of attempts by Congress to define it as early as 1802. It is a legal term that attempts to deal with jurisdictional, land title, sovereignty and treaty rights issues. There have been numerous Congressional and judicial attempts to define the term over the years. However, the geographic boundaries of the term are not immediately clear even though that is the intent of the legal definition. As you know, these "fuzzy" legal definitions engender much debate as well as litigation.
In 1948, there was a definition of "Indian country" enacted by Congress which reads as follows:
Except as otherwise provided in sections 1154 and 1156 of this title, the term "Indian country," as used in this chapter, means (a) all land within the limits of any Indian reservation under the jurisdiction of the United States government, notwithstanding the issuance of any patent, and including rights-of-way running through the reservation, (b) all dependent Indian communities within the borders of the United States whether within the original or subsequently acquired territory thereof, and whether within or without the limits of a state, and (c) all Indian allotments, the Indian titles to which have not been extinguished, including rights-of-way running through the same. (18 U.S.C. 1151)
Earlier legal attempts to define "Indian country" were usually specific listing of geographic boundaries as enacted by Congress. (See Act of March 30, 1802, section 1: 2 Stat. 139. See also American Fur Co. v. United States, 8 U.S. 137 (1829). In an 1834 Act, another approach to defining the legal term "Indian country" was essentially to create a residual land base. In essence, "Indian country" was "that part of the United States west of the Mississippi" not within certain states, "to which the Indian title has not been extinguished." See Bates v. Clark, 95 U.S. 204 (1877).
(See Monroe E. Price, _Law and the American Indian_ (New York: Bobbs-Merrill, 1973), pp. 32, 115, 117 for a more detailed discussion of this legal term. See also, Sonosky, "State Jurisdiction over Indians in Indian Country," 48 North Dakota Law Review Rev. 551 (1972).
Thus, the legal term "Indian country" is a product of the conquest ideology that was generated by Non-Native Americans in the 19th and 20th centuries. As such, it sought to deal with the legal, racist and power relationships in the history of U.S. and Native American relations. Essentially, its definition changes over time to reflect the changes in power between Native Americans and Non-Native Americans. These changes produce legal problems and paradoxes which are part of the problem with racist terms (they have to be continually adjusted to fit new configurations of power between Native Americans and Non-Native Americans). Generally, law follows custom and this term grew and changed as dominant culture/conquest ideologies were reconfigured to suit changes in customary dealings with Native American people (for instance, the transition from the autonomous treaty making phase to the subjugation/reservation phase). An attempt to rationalize these changes as a "body of law and precedent" is a contradiction since racism and those operating under racist assumptions are not rational (racism is about maintenance of power by the dominant group over the subjugated group through legal and extralegal means). Thus, when extralegal means are needed and practiced to maintain power relationships it is often the role of the court system to make the extralegal legal. Customs such as racism, sexism, etc. become the norm and the law sanctions and legitimates such customary practices.
Having said all of that, "Indian country" is a short hand legal term that summarizes an amorphous body of legal definitions in history that the dominant society and its courts have agreed upon. The resulting body of law and definitions called "precedent" is an integral part of the way the law works. Thus, going through the U.S. legal system necessitates submission by Native Americans to historical and contemporary racist assumptions inherent in the process. Changing language is better done through custom and culture than it is in legal disputes.
For instance, I am more dismayed at the continued use of "Redskin," "Chief" and "Brave" than I am over the use of "Indian country." Current users of these sports names argue over the objection of most Native Americans that their continued use is to "honor" Native American people even though Native Americans don't feel honored (as a test case, I have recently taken to using "cracker," "honky," "redneck," "peckerwood," "white trash" and "stump jumper" as terms to "honor" white people. The results of this testing have been that they don't feel honored even though I say it's my way of honoring them -- perhaps this is why we don't have a Houston Honkies sports team). Changing language can only be done effectively in the media, educational institutions and culture of the society and when it changes there then the law follows because it reflects and follows the prevailing customs of society. When you are in the discourses of Native American law, you are in the belly of the beast of conquest and conquest ideology. For me as a Native American, if you are to change things then its best to be outside the beast rather than inside it. Civil disobedience, the American Indian Movement, and the Civil Rights movement are clear examples of these processes in recent history. I hasten to point out that this does not preclude Native American alliances with sympathetic persons within the law. Real societal change is always multifaceted and multilayered.