During the military reforms of Prime Minister Manuel Azaña, he solicited permission to go into the reserves and settled down in Burgos, from where he participated in the military conspiracy to overthrow the Popular Front government. On the night of the July 18–19, 1936 he seized the civil government of Burgos. He was a member of the "Junta de Defensa Nacional" and president of the Technical Board of the State, the core of the future national government, as well as chief of staff of the Army. He participated in the War in the North resulting in the conquest of Biscay, Cantabria, and Asturias.