The Sacred Buffalo Vision by Robert J. Juneau and Robert C. Juneau pg.137

For purposes of defining a “resident” of Montana for election precincts, the 1911 Montana Legislature excluded “any person living upon an Indian or military reservation.”

In 1913, a Montana Attorney General’s opinion declared that even Indians who owned land in fee but who took part in the transactions of the tribe were not entitled to vote. In 1914, the Montana Supreme Court ruled that the boundaries of a voting precinct should not include any territory other than the granted non-Indian lands.

 In 1919, the Montana Legislature enacted laws prohibiting the establishment of a voting precinct within or at the premises of any Indian agency or trading post. In 1919, the Legislature, in enacting procedures related to the creation of counties, required voters to be the “qualified electors of the county, whose names appear on the official registration books and who are shown to have voted at the last general election.”

This law disallowed the Blackfeet Indians from voting in the creation of Glacier and Pondera Counties on the Blackfeet Indian Reservation, a clear violation of the U.S. Constitution and Congress plenary powers over Indian land and sovereignty, to say nothing of establishing political slavery for robbery of Indian lands and implementing state jurisdiction and control over free treaty Indians.
-The Sacred Buffalo Vision by Robert J. Juneau and Robert C. Juneau
pg.137