China is one recession away from another Tienanmen Square. The reason the Chinese people put up with CCP rule is that the party guarantees continuous economic growth. At some point, maybe not too far off considering the Chinese housing bubble, the party won't be able to deliver. Once the inevitable recession happens there will be a crisis of leadership, and it's impossible to know what will happen after that. What we can be sure of, however, is that China's brittle authoritarian system as it exists now cannot last. That doesn't mean democracy will come there or that civil war will start, but it does mean that China will have serious enough domestic problems in the medium range that an eclipse by it of the United States is almost farcical.
As for Russia, goldfinger0303 is right. It's all about Putin. Russia doesn't really have independent institutions, everything exists to serve Putin and the corrupt political class's system of patronage. Putin will stay in power until at least 2024 under the new six year terms the Russian president has. I don't think we can say anything with any degree of certainty about what a post-Putin Russia will look like. He'll have ran the place for a quarter century is he steps down then and will be the defining figure of post-Soviet government there. Putin's making himself indispensable to the Russian state, and that's dangerous since, like all men, he'll someday die or be too old to lead and leave Russia without the institutions necessary to run a government without a strongman.
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Someone explain String Theory to me
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