The demise of communism in the former Soviet Union and the massive political and economic changes in China are the stunning transformations of our century. Two central questions are emerging: Why did different communist systems experience different patterns of transition? Why did partial reforms in the Soviet Union and China turn into revolutions?

Minxin Pei is Senior Associate and Director of the China Program, Carnegie Endowment for International Peace.

Read More by Minxin Pei:

• China's Trapped Transition: The Limits of Developmental Autocracy