"Embick sought logistics assistance from senior armored and infantry corps commanders, who insisted the maneuvers be as realistic as possible. Loudspeakers would blare the recorded sounds of battle, canister smoke would shroud the battlefield, and bags of white sand would be dropped from aircraft to simulate the impact of artillery shells. U.S. Army Air Corps spotter and reconnaissance planes would gather intelligence, while transports would deliver troops to newly constructed airfields. Planners stockpiled millions of rounds of blank ammunition, and Embick established rules to govern when units would join the line of fire and what kinds of “casualties” they’d suffer. His goal was not only to determine who could “kill” whom, but also to test the time it took medical units to transfer the “wounded” to rear-area combat hospitals. Finally, Embick appointed and trained hundreds of maneuver “umpires,” who, armed with clipboards and armbands, would monitor and assess units and leaders according to a complex grading system.
While the umpires’ conclusions were important, even more important, from Embick’s perspective, was feedback from individual commanders, who were to assess their own performance and that of their troops. Embick’s goal was not to determine winners and losers of the exercises, but to create an effective training regimen for the coming war."
"The 1940 maneuvers began in May with 70,000 soldiers, who trained and “fought” in four separate exercises of three days each, beginning on May 9. These first maneuvers, Embick said, were “experiments,” not contests. The first was to see whether armored units could actually mobilize and travel long distances. To test this, the War Department ordered Maj. Gen. Walter C. Short’s IV Corps to move from its Fort Benning headquarters in Georgia to Louisiana—550 miles in six days, the longest motor march ever undertaken by the U.S. Army. Soon after arriving in Louisiana, IV Corps was thrown into a series of corps-on-corps exercises that pitted Short’s armored columns (the “Blue Army”) against Krueger’s IX Corps (the “Red Army”). As military historian Christopher Gabel noted:
In the first exercise, Red Army took the offensive, crossing the Calcasieu while Blue Army defended the river line. In the second exercise, Blue Army attacked, enveloping both flanks of the Red force. The third maneuver again saw Blue on the attack, this time with penetrations of the Red line at Slagle and Hornbeck. In the fourth exercise, the provisional tank brigade and the 7th Mechanized Cavalry Brigade were combined into a provisional division totaling some 382 tanks—the first armored division in Army history. This force spearheaded a Red Army attack, which the Blue force countered with an antitank defense extending as far east as Gorum and Flatwoods.
Embick followed up, crisscrossing the “battlefield” to question commanders and soldiers on both sides and reaching some preliminary conclusions on America’s combat readiness. What he found was not encouraging—the Army evidently had a lot to learn about mobile warfare. Vehicle breakdowns, repair team shortages, repeated traffic jams and poorly worded orders were all common. More important, senior commanders’ failure to lead from the front led to uncoordinated attacks and jumbled defenses. “Commanders and staffs mistakenly believed that they could run the war from headquarters,” Gabel noted, “relying on maps and telephones, much as they had in the static warfare of 1918.”
Louisiana Maneuvers (1940-41) » HistoryNet