First - this is about Hillary Rodham Clinton, not Health Care Reform. :)
Secretary of State Clinton has announced she "can't imagine" serving in her current capacity for another four years, because its "very challenging" (surely there are other reasons too, but that's what she said). I think if anyone could do it for 8 years it'd be HRC - but having been in her position, heck if I know. That said, far be it from me to second-guess her judgment on whether or not she is fit to serve 8 years.
The automatic question then, is who should follow her? Foreign Policy has a couple of ideas...
Early frontrunner: John Kerry
Kerry has been campaigning for the job since before Obama's election. He looked eminently diplomatic in convincing Afghan President Hamid Karzai to agree to a new election. And his steady stewardship of the Senate Foreign Relations Committee seems to have erased doubts about his ability to head an organization. He's got international profile and his Massachusetts seat is (relatively?) safe.
I like John Kerry better as a Senator, and I think he should stay on the Foreign Relations Committee. He'd make a great Sec. of State for so many reasons - but I think its more important to keep him where he is.
Gray eminence: Richard Lugar
Lugar is well-respected on both sides of the aisle, has strong nonproliferation credentials, deep expertise on international issues, and has been a staunch defender of the State Department bureaucracy. His appointment would signal Obama's continued commitment to having a bipartisan cabinet. The question will be: As an 80-year-old man in 2012, has he got the vigor to do it?
It'd be nice to get the most senior Republican out of the Senate. Unfortunately, unless HRC steps down before 2012, Lugar would surely win reelection in 2012 (he took 87% of the vote last time), and Gov. Mitch Daniels (R) would appoint a Republican as a replacement... who would then have 6 years to insinuate himself before he had to actually run for office.
I think that'd be a pretty bad outcome.
Waiting in the wings: Jim Steinberg
Steinberg is said to be somewhat disappointed at not getting a higher posting in the first round of the Obama appointments, but he's been amazingly active as deputy secretary of state, injecting himself into almost every issue and taking on Asia as his personal policy domain. He knows the building, which would make for a smooth transition. His reported clashes within the department and throughout the interagency would be his only drawback.
I like the idea of appointing a bureaucrat, since it won't hurt the legislative balance. I like that Steinberg is apparently a bit of a hothead, and favors sticks over carrots in resolving the genocide in Sudan (which may flare up again in January 2011, when the autonomous southern region holds a referendum on whether or not to secede).
Already in the cabinet: Susan Rice
Rice spends more time in Washington than most of her U.N. ambassador predecessors. With full cabinet rank, she's not shy in playing a role in foreign policy so far, and she benefits from her close personal relationship with Obama. Her appointment would signal a redoubling of the effort toward engagement and international diplomacy. But if times are tough and wars are raging, her chances might be slimmer.
I really like Secretary Rice where she is, and think the work she's doing with the south African regional powers is extraordinarily important. I'd hate to move her and risk ignoring Africa again.
A bridge too far: Richard Holbrooke/George Mitchell
Either of these senior envoys would have seemed like a logical successor to Clinton a year ago. Both men are grand poobahs of the foreign policy establishment, but their respective efforts to solve major international problems have thus far met with limited success. If either the situations in Afghanistan or the Middle East were to vastly improve between now and 2012, however, their stock would go straight up.
Holbrooke did eventually come around on Iraq - it only took him three years - but honestly, isn't there something better for him to do?
I think George Mitchell should stay where he is, working on the Middle East peace process. He's a good negotiator and we need to try and maintain some consistency with regards to Israel.
Always the bridesmaid: Chuck Hagel
A media darling, Hagel's name is always floated when one of these opportunities come up. Fiercely independent and blunt, his style never seemed to match up with the academic intellectualism of Obama. What's more, he reportedly turned down high-level ambassadorships because he didn't want to travel, so it's doubtful he would be in serious consideration.
I like Hagel well enough - while a Republican Senator, he told Karl Rove that policy is more important than politics, and belittled Cheney's opinions on war. If its true that he's not in the running, then he's not in the running. When Obama was previously asked if Hagel might receive a cabinet position, he said: "Chuck Hagel is a great friend of mine and I respect him very much", which sounds to me like 'heck no!'
Dark horse: Gen. David Petraeus
When Petraeus's term as head of Central Command winds down, there will be nationwide speculation about his next role. If the international atmosphere is one of danger and uncertainty, Petraeus's stature could help him overcome concerns about having a military man be the face of American foreign policy. Obama has also shown a willingness to co-opt potential presidential rivals, and the general has been regularly mooted as a Republican contender in 2012 -- notwithstanding his vigorous disavowals of any political ambitions.
The nice thing about Petraeus is his opinions on force projection - from "Military Influence And the Post-Vietnam Use of Force", to "Why We Need FISTs—Never Send a Man When You Can Send a Bullet", his oeuvre is replete with examples of his strong intellectual advocacy against 'boots on the ground'. The COIN focused surge that made him a household word was fundamentally against his character - a 'Nixon goes to China' moment.
That said, he isn't a diplomat, and he knows it. As Tom Ricks discusses in The Gamble, Petraeus recognizes the need for diplomacy - but he hires people to do it for him, such as Sadi Othman. Petraeus may provide a strong opposition against invading anyone else, but if we have to worry about Obama invading anyone, then we have bigger problems than who to pick for Sec. of State.