Wainwright was promoted to colonel in 1935, and served as commander of the 3rd US Cavalry Regiment until 1938, when he was promoted to brigadier general in command of the 1st Cavalry Brigade at Fort Clark, Texas.
Wainwright was promoted to colonel in 1935, and served as commander of the 3rd US Cavalry Regiment until 1938, when he was promoted to brigadier genera.l in command of the 1st Cavalry Brigade at Fort Clark, Texas