The weak political system of the Second Spanish Republic and the rise of nationalism led to the outbreak of the Spanish Civil War in July 1936. Shortly into the conflict, Puerta de Hierro was seized by the Juventudes Socialistas Unificadas, who used the grounds to accommodate themselves. Later that year the club was occupied by the Rosal Column, who established their headquarters in the club house and dug out several trenches and machine gun nests throughout the estate, including the golf courses. The club, which was situated in the very centre of the Madrid front, was, for the most part, Republican territory, while the Casa de Campo marked the beginning of the Nationalist area. It was only during this time that the club had no president (1936-1939).