At considerable risk to their own careers, the four key officers began to complain, in varying ways and in varying degrees. The four advisers were Colonel Wilbur Wilson, III Corps (the main area around Saigon, and west and north of it); Colonel Dan Porter, IV Corps (the rest of the Mekong Delta); Lieutenant Colonel John Paul Vann, 7th Division (the northern tier of the Delta); and Lieutenant Colonel Fred Ladd, 21st Division (the southern tier of the Delta).
