The invasion of Poland led Britain and France to declare war on Germany on 3 September. However, they did little to affect the outcome of the September Campaign. No declaration of war was issued by Britain and France against the Soviet Union. This lack of direct help led many Poles to believe that they had been betrayed by their Western allies. Foreign Secretary Edward Wood said they were only obligated to declare war on Germany due to the first clause of the Anglo-Polish Agreement in 1939.