Given Secretary Clinton’s working lunch with Treasury Secretary Tim Geithner today and speculation that both want to take over the China file, I asked Minxin Pei, a noted China expert at the Carnegie Endowment for Interntional Peace, for his thoughts on who should spearhead the China brief – Clinton or Geithner?

The right answer is neither. In the past, the most successful handler of U.S.-China relations was either the president himself (both Bush Sr. and W, for example) or the National Security Advisor (Kissinger, Brzezinski, and Berger) who has the ear of the president.

The reason is quite simple:Given the complexity of the relationship and the conflicting interests among various bureaucracies, the only person who can manage this relationship and balance competing interests would be the president or his national security advisor.

Hillary Clinton might want to be spearhead this relationship, but she might want to think twice. She would be treading on many toes — the Pentagon, the Treasury, USTR, and, needless to say, Congress. And for what? The relationship is not in deep trouble. There are some problems to be ironed out. She would be spending a lot of energy but getting very little in return.

As for Geithner, I doubt whether he wants to repeat what Paulson did. Geithner has neither the personal interest in China nor the political backing from the very top to handle the U.S.-China brief. Paulson supposedly got a commitment of support from W as a condition of signing on as the Treasury Secretary. In any case, Geithner will be spending most of his time on rescuing the U.S. economy. If I were him, I would do anything to avoid 14-hour flights to Beijing and the jetlag.

That leaves one possible choice — Joe Biden. The Chinese press is already floating unconfirmed rumors — out of Japan — that Biden will be heading the Strategic Economic Dialogue between the U.S. and China. That could be wishful thinking on Beijing’s part because this would give him even more face than what Paulson has done.