In July 1944, the U.S. Army and Marines recaptured Guam from the Japanese at a cost of 1,783 Americans killed and ~6000 men wounded. ~18,000 Japanese died. After the battle, the Allies developed five airfields on Guam to attack targets in the Western Pacific and on mainland Japan.
Occupying Guam, racial tensions developed among enlisted U.S. Marines when an all-black supply depot company arrived. White Marines, trying to prevent blacks from socializing with Guamanian women, shouted racial slurs, threw rocks and occasional smoke grenades into the depot area.
Tension escalated when a white sailor killed a black Marine in a fight over a woman; and a black sentry fatally wounded a white Marine who was harassing him. Subsequently, each of these men was court-martialed for manslaughter.
On Christmas Eve 1944, with rumors circulating among black and white Marines that one of their own had been injured or killed, truckloads of angry Marines harassed each other’s turf without injuries. On Christmas day, two black Marines were killed in separate incidents by drunken whites.
On December 26, a jeep of white Marines fired on the black Marine depot, injuring a white MP. A group of armed blacks chasing the whites’ jeep, were stopped at a roadblock and charged with unlawful assembly, theft of government property and attempted murder.
43 Marines (including a few whites) were court-martialed and given prison terms of several years each. The National Association for the Advancement of Colored People later successfully campaigned to have the guilty verdicts overturned and the black marines were released from prison in 1946.