The main purpose of this book has been to identify Gorbachev's and Yeltsin's evolving strategies for building, maintaining, and recouping their authority as leaders. In the present chapter, I turn from description and analysis to explanation. Why did Gorbachev and Yeltsin choose these strategies at each stage of their administrations? That these two men occupy center stage in the book should not lead us to assume that their personalities and personal beliefs were always the primary – much less, sole – determinants of their choices. Other factors delimited and shaped their behavior at given points in time: (1) the political organization of the regime and the interests that dominated within it; (2) the regime's ideological traditions and legitimizing credos; (3) the prevailing climate of opinion within the political establishment; (4) the process of political competition for power and authority among elite actors; (5) mobilized social forces within the country; and (6) direct and indirect pressures from abroad.

When Khrushchev and Brezhnev were in power, these factors were relatively limited, stable, and predictable. Politics was a private affair and was dominated by the political and organizational interests of the Party-State apparatus and the budgetary interests of the military–industrial complex. Marxism–Leninism's hostility to liberalism defined the limits of winnable political advocacy. Political competition for power and authority took place within the narrow confines dictated by the political organization and ideological anti-liberalism. Social forces within the country were dominated by the Party-State apparatus; they could affect indirectly the climate of opinion within the political elite but could not mobilize autonomously against that elite.