Prior to the 1970s there was not a decade in the turbulent history of the Soviet Union that did not put the political system to the test. By comparison, the last ten years were a period of calm; consequently, we must bear in mind that the policies we have examined in this book were formed and carried out in an unusually benign atmosphere. But beginning in the 1980s the Soviet political system faces two further tests, one political and one economic. The first is a sweeping change in political leadership. Within the next few years power will pass to a new generation of rulers, not only in the Politburo, but also in the top several hundred positions of the party and government. Incredible as it may seem, this will be the first true succession in the Soviet elite since the Great Purge of 1938–9. One may say without much exaggeration that nearly two-thirds of a century after the 1917 Revolution, the Soviet political system is just beginning its third generation. The second test is economic. The country will face shortages of several key resources, particularly energy, manpower, and capital, each of which has the potential to create a crisis as serious as the one in agriculture in the 1960s. Together these two impending challenges may create a climate with more possibilities for changing the traditional structure and rules of Soviet politics than at any time since the 1920s.