meeting with Goerdeler, Witzleben agreed to form a network of army commanders willing to take part to prevent a war against the western powers. But support in the officer corps for a coup had dropped sharply since 1938. Most officers, particularly those from Prussian landowning backgrounds, were strongly anti-Polish. Just before the invasion of Poland in August 1939, General Eduard Wagner who was one of the officers involved in the abortive putsch of September 1938, wrote in a letter to his wife: "We believe we will make quick work of the Poles, and in truth, we are delighted at the prospect. That business must be cleared up" (Emphasis in the original) The German historian Andreas Hillgruber commented that in 1939 the rampant anti-Polish feelings in the German Army officer corps served to bind the military together with Hitler in supporting Fall Weiss in a way that Fall Grün did not. The officers who had willing to consider taking part in a putsch in 1938 loyally rallied to the Nazi regime in 1939 when faced with the prospect of war with Poland. Likewise, the Catholic Bishop Galen delivered a sermon calling the war against Poland a struggle to "win a peace of freedom and justice for our nation". This nevertheless marked an important turning point. In 1938, the plan had been for the army, led by Halder and if possible Brauchitsch, to depose Hitler. This was now impossible, and a conspiratorial organisation was to be formed in the army and civil service instead. The opposition again urged Britain and France to stand up to Hitler: Halder met secretly with the British Ambassador Sir Nevile Henderson to urge resistance. The plan was again to stage a coup at the moment Hitler moved to declare war. However, although Britain and France were now prepared to go to war over Poland, as war approached, Halder lost his nerve. Schacht, Gisevius and Canaris developed a plan to confront Brauchitsch and Halder and demand that they depose Hitler and prevent war, but nothing came of this. When Hitler invaded Poland on 1 September, the conspirators were unable to act. Outbreak of war The outbreak of war made the further mobilization of resistance in the army more difficult. Halder continued to vacillate. In late 1939 and early 1940 he opposed Hitler's plans to attack France, and kept in touch with the opposition through General Carl-Heinrich von Stülpnagel,