It now seems more likely that Kennedy had already reached an agreement with Moscow through unofficial secret service channels. Khrushchev, who had been kept busy managing a split in the international communist movement, finally decided to pay attention and clamp down on the notorious ‘salami-slicing’ activities of the notably wilful East German leader, Walter Ulbricht, which had led to the crisis in the first place. Khrushchev was only too keen to find a face-saving formula – as was Kennedy. The end of the ‘Checkpoint Charlie’ confrontation in effect meant the end of the Berlin crisis. Both superpowers had other fish to fry.
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.