Hitler was incensed by this counterthrust but quickly cancelled his order for the invasion. Then, in a wild gamble that France and Great Britain would not meet their treaty obligations to Poland, and knowing he had nothing to fear from the Soviet army, Hitler ordered his troops to strike east into Poland on September 1, 1939. Two days later, on September 3, France and Great Britain declared war on Germany. World War II had begun. And less than two years after that, Hitler scrapped his pact with Stalin and sent some 3 million Nazi soldiers pouring into the Soviet Union on June 22, 1941.
By the 1970s, the Stasi had decided that the methods of overt persecution that had been employed up to that time, such as arrest and torture, were too crude and obvious. It was realised that psychological harassment was far less likely to be recognised for what it was, so its victims, and their supporters, were less likely to be provoked into active resistance, given that they would often not be aware of the source of their problems, or even its exact nature. Zersetzung was designed to side-track and "switch off" perceived enemies so that they would lose the will to continue any "inappropriate" activities.