My old friend Kurt Campbell suggests in yesterday's Financial Times that China may be running out of patience with North Korea. He writes that the lack of reform in the North, increasingly brazen behaviors such as Pyongyang's recent nuclear test, and China's growing ties with South Korea mean that Beijing may conclude that North Korea is more trouble than it's worth. Still, new problems emerge if North Korea shifts from vassal state to rogue state. Twitter - @jessicamcwade