[196] In 1882, he signed the Edmunds Act into law; the legislation made polygamy a federal crime, barring polygamists both from public office and the right to vote.[196]

Native American policy[edit]
Portrait of Arthur by Eastman Johnson (1887)
The Arthur administration was challenged by changing relations with western Native American tribes.[197] The American Indian Wars were winding down, and public sentiment was shifting toward more favorable treatment of Native Americans. Arthur urged Congress to increase funding for Native American education, which it did in 1884, although not to the extent he wished.[198] He also favored a move to the allotment system, under which individual Native Americans, rather than tribes, would own land. Arthur was unable to convince Congress to adopt the idea during his administration but, in 1887, the Dawes Act changed the law to favor such a system.[198] The allotment system was favored by liberal reformers at the time, but eventually proved detrimental to Native Americans as most of their land was resold at low prices to white speculators.[199] During Arthur's presidency, settlers and cattle ranchers continued to encroach on Native American territory.