Ludwig Beck
In 1940, Planck, Popitz, Ulrich von Hassell and General Ludwig Beck drafted a "Provisional Constitution" on the assumption that the forthcoming attack on the Western Front would overthrow Hitler's regime. Even afterwards, Planck stayed in the conservative resistance circles around Carl Friedrich Goerdeler and was involved in the preparations for the 20 July plot. This led to his arrest on 23 July 1944, after which he was taken to the Gestapo headquarters at the "Reichssicherheitshauptamt" (RSHA).