direct or indirect support of other components of the Nation's armed forces." It believed the primary target was the adversary's army. The most vocal opponent of this view was Assistant Chief of the Air Service, Brigadier General Billy Mitchell, who saw in strategic bombing the proper use of air power. Close air support and interdiction, he asserted, only perpetuated trench warfare and the horrors of World-War I-like slaughter. He argued for a force that could strike directly at an enemy's vitals, "centers of production of all kinds, means of transportation, agricultural areas, ports and shipping," forcing "a decision before the ground troops or sea forces could join in battle."
Mitchell's actions created opponents as well as adherents. A series of highly publicized ship-bombing tests begun in 1921 overshadowed the ideas he had espoused in books such as Winged Defense: The Development and Possibilities of Modern Air Power―Economic and Military. Air Service bombers sank several unmanned, anchored ships, including battleships. Mitchell's apparent success, despite poor bombing accuracy, diverted both the public's and the Congress's attention from more critical aerial achievements and issues of the period. Mitchell's troubles with Army and Navy leaders eventually led to his court martial after he spoke intemperately about the crash of the airship Shenandoah in 1925. (He blamed the loss on "incompetency, criminal negligence, and almost treasonable administration.") President Coolidge, famous for his reticence and nicknamed "Silent Cal," expressed a widely-held view when he contended, "General Mitchell [has] talked more in the last three months than I [have] in my whole life."
Behind such scenes, Chief of the Air Corps Major General James Fechet urged his officers in 1928 to look beyond the battlefield, beyond close air support, and find a way for the Air Corps to win a war independently. He imposed only three limitations: First, the Air Corps had to get the most for any money available. Second, civilians could not be targets of aerial attack. Secretary of War Newton Baker had ruled earlier that doing so "constituted an abandonment of the time-honored practice among civilized people of restricting bombardment to fortified places or to places from which the civilian population had an opportunity to be removed." Americans would not undertake terror raids, he said, "on the most elemental ethical and humanitarian grounds." Third, anything the Air Corps did would have to solve or avoid the evils of trench warfare.
One officer who answered Fechet's challenge was Lieutenant Kenneth Walker. Conventional wisdom taught that while airmen achieved high accuracy when they bombed from high altitudes, they exposed themselves to deadly ground fire. Walker showed that daylight high-altitude
