The Mexican Revolution (1910–20) produced protracted upheaval along the American border. Streams of refugees fled the fighting, and rebels used the American Southwest desert as their bolthole. The instability helped to prompt admission of Arizona and New Mexico to the Union (1912). Their incorporation did not prevent a series of skirmishes erupting, culminating in the Battle of Ambos Nogales (1918) on the Arizona border, where military advisers from Germany, America’s Great War adversary, accompanied Mexican forces. In Oklahoma, successive land runs had hemmed the remaining Indian reservations into an eastern pocket of the territory, to be merged and extinguished with admission to statehood (1907). The Yukon and Klondike gold rushes brought an influx of American ‘stampeders’ to Alaska, leading to its organization as a territory (1912), and allowing the United States to browbeat a favourable result to its border dispute with Canada over the mouth of the Lynn Canal.
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