ASK NOT FOR WHOM THE BELL TOLLS...:

The crisis marks the most serious challenge to Putin's 23-year rule--and a moment of uncertainty for Chinese leader Xi Jinping. Xi has cast China's bond with Russia as a bulwark against U.S. influence in the world and put his personal relationship with Putin at its center.

Now, Russia is in disarray and Putin appears weakened.

"This is that pessimistic scenario that China was afraid of--that Putin, when he started the invasion, will eventually damage the stability of the regime," said Temur Umarov, a fellow at the Carnegie Russia Eurasia Center.

Tweet   @brothersjudd