We have seized the coastal area of Sansapor and the nearby islands of Amsterdam and Middelburg, at the western tip of Dutch New Guinea, nearly 200 miles beyond Noemfoor and slightly more than 600 miles southeast of the Philippines. . . . The operation was an amphibious one, the ground troops acting in coordination with naval and air forces. The enemy base at Manokwari, the pivot of the defense of the Vogelkop Peninsula, is now bypassed and useless. Its garrison, 15,000 strong . . . is now isolated with its only possible escape route to the south over hazardous terrain of swamp and jungle. Our air bases are now established from Milne Bay along the entire coast of New Guinea. The enemy is no longer able to operate in this area, either by air or sea, beyond the Halmahera-Philippine line which is the main defense cover for his conquered empire in the Southwest Pacific. Should this line go, all of his conquests south of China will be imperiled and in grave danger of flank envelopment.
Charles A. Willoughby et al., eds., Reports of General MacArthur: The Campaigns of MacArthur in the Pacific, 2 vols. (Washington, DC: U.S. Government Printing Office, 1966), 1: 118–120. .