Despite being formally less democratic, the Chinese government is in practice more responsive to its constituency than the US government. I have to think that class character of the parties is the determining factor. The CPC is, despite everything, still a proletarian party. In the US, the two parties are both directed by the interests of the haute bourgeoisie, with the Republicans pulling votes from the petit bourgeoisie, and the Democrats pulling votes from the professional-managerial class.