Only after the conspirator General Helmuth Stieff on 7 July 1944 had declared himself unable to assassinate Hitler on a uniforms display at Klessheim castle near Salzburg, Stauffenberg decided to personally kill Hitler and to run the plot in Berlin. By then, Stauffenberg had great doubts about the possibility of success. Tresckow convinced him to go on with it even if it had no chance of success at all, "The assassination must be attempted. Even if it fails, we must take action in Berlin", as this was the only way to prove to the world that the Hitler regime and Germany were not one and the same and that not all Germans supported the regime.