American spelling: to remove military forces, equipment, and authority from a location or region.
From de- (remove) plus militarize. This American spelling became standard in U.S. state department documents and international treaties during the 20th century.
The Panama Canal Zone was demilitarized through treaty in 1977 because both the U.S. and Panama needed to trust each other enough to let the canal operate peacefully—it's one of the world's most strategically important waterways.
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