As a result of the lessons learned from the PID's training and exercises, Krueger was able to offer recommendations for improvements to the triangular division concept, including taking advantage of mechanization and fast-paced tactics. The troops who took part in the PID experiment called themselves the "Blitzkruegers"; the triangular division model was adopted, and became the Army's standard design for infantry divisions in World War II. World War II Training in the United States Krueger became commander of IX Corps on 31 January 1940. This corps was created to control units of the Third Army engaged in large scale maneuvers in 1940, in which Krueger's IX Corps conducted a series of mock battles against Walter Short's IV Corps. On 27 June, Krueger became commander of the VIII Corps. On 16 May 1941, he was promoted to lieutenant general, in command of the Third Army. He also became commander of the Southern Defense Command on 16 July 1941. Krueger asked for—and got—Colonel Dwight D. Eisenhower assigned to him as his chief of staff. The Louisiana Maneuvers pitted Krueger's Third Army against Lieutenant General Ben Lear's Second Army. The maneuvers were a test ground for doctrine and equipment, and gave senior commanders experience in maneuvering their formations. In the first phase, Krueger quickly proved himself to be the more modern general. He responded adroitly to a changed battle situation by re-orienting his front from northeast to northwest, and was able to inflict a series of reverses on Lear's forces. In the second phase, Krueger had a superior force, and had to advance on Shreveport, Louisiana. Lear's forces conducted a stubborn withdrawal, demolishing bridges in order to slow Krueger down. Krueger responded by sending Major General George S. Patton, Jr.'s 2nd Armored Division on a wide flanking maneuver through Texas. Afterwards, Eisenhower became the head of the War Plans Division, and was replaced as Krueger's chief of staff by Colonel Alfred M. Gruenther. After he too was transferred, Krueger replaced him with Colonel George B. Honnen. Krueger wrote to a friend that Sixth Army It therefore came as a surprise when Krueger was informed that a theater commander had requested his services. General Douglas MacArthur, the Supreme Commander of the Southwest Pacific Area (SWPA), said that he was "especially anxious to have Krueger due to my long and intimate association with him". This too came as a surprise to Krueger; while the two