In the Asian Wall Street Journal, Ted Galen Carpenter says we should play the China Card to bring down the Kim Regime--but with the US-ROK Alliance as bidding material:

While there is relatively little the U.S. can do to ease Beijing's fears of being swamped with refugees, beyond offering to help with financial assistance, the second fear is easily addressed. Washington can pledge that, if China helps bring down Kim's regime and end North Korea's nuclear-weapons programs, the U.S. would end that security alliance and withdraw all its forces from the peninsula. This would, of course, be conditional on China also agreeing not to deploy any military forces on the peninsula.

Such a concession would do no more reflect the reality that Seoul is already drifting into Beijing's orbit. Trade between South Korea and China is expanding rapidly, and Seoul increasingly sides with Beijing rather than Washington on issues ranging from relations with Japan to the status of Taiwan. That foreign-policy posture is causing complications for Washington, as demonstrated by President Roh Moo Hyun's attempts to downplay the significance of the July 5 missile tests. And the U.S. military presence in South Korea is already in the process of being cut by a third, to 25,000 troops in 2008. Completing the process in the event of a reunified peninsula would help give Washington more room for maneuver, especially as a united Korea could be expected to forge even closer diplomatic and economic ties with China.