I think that title is over-promising, actually. The key explanatory innovation is the role of moral ideas in overthrowing the old order. Aron writes, for example:
LIKE VIRTUALLY ALL modern revolutions, the latest Russian one was started by a hesitant liberalization "from above" -- and its rationale extended well beyond the necessity to correct the economy or make the international environment more benign. The core of Gorbachev's enterprise was undeniably idealistic: He wanted to build a more moral Soviet Union.At least from an ideational perspective, the argument is familiar. I'm reminded of the edited volume from Richard Ned Lebow and Thomas Risse-Kappen, International Relations Theory and the End of the Cold War, published in 1995. Ideas are contrasted with material interests as a mobilizing factor in historical change. So Leon's argument builds on themes that have been common in international relations literature for some time. Aron's book on this is forthcoming, and looks interesting: Roads to the Temple: Truth, Memory, Ideas, and Ideals in the Making of the Russian Revolution, 1987-1991.
For though economic betterment was their banner, there is little doubt that Gorbachev and his supporters first set out to right moral, rather than economic, wrongs. Most of what they said publicly in the early days of perestroika now seems no more than an expression of their anguish over the spiritual decline and corrosive effects of the Stalinist past. It was the beginning of a desperate search for answers to the big questions with which every great revolution starts: What is a good, dignified life? What constitutes a just social and economic order? What is a decent and legitimate state? What should such a state's relationship with civil society be?
"A new moral atmosphere is taking shape in the country," Gorbachev told the Central Committee at the January 1987 meeting where he declared glasnost -- openness -- and democratization to be the foundation of his perestroika, or restructuring, of Soviet society. "A reappraisal of values and their creative rethinking is under way." Later, recalling his feeling that "we couldn't go on like that any longer, and we had to change life radically, break away from the past malpractices," he called it his "moral position."