<i>"China has no interest in a unified Korea that would presumably be allied with the US."</i><p>Actually, China may have a lot to gain from a unified Korea, since they would suddenly become a much larger market for Chinese exports.<p>In the 1960s, China may have had a lot in common politically with North Korea, but today, China's economy looks a lot more like that of a capitalist country than an old-style communist one.<p>And China would have a lot to lose by getting involved in a war the the US, one of its biggest trading partners. (Not to mention that China holds about a trillion dollars worth of US Treasury securities.)