The second of these acting heads of division was Major William "Billy" Mitchell, a General Staff officer who had testified before Congress in 1913 against transfer of aviation from the Signal Corps. As a result of negative publicity regarding its airplanes in Mexico, Mitchell and the Aviation Section came under severe criticism during this period. Mitchell defended the department, insisting that the U.S. firms did not produce better aircraft, but the outcry produced several long-term results, including instructing Mitchell in political tactics, participation in which ultimately resulted in his court-martial at the end of his career.