No question: Kerry deserves to be the next secretary of state. (Clinton, who looks exhausted, has said repeatedly she won’t stay for a second term.) First, as longtime chairman of the Senate Foreign Relations Committee, Kerry knows the issues cold. Second, in his first term, Obama called on Kerry many times to serve as de facto envoy to Afghanistan and Pakistan, and he did well, persuading Afghan president Hamid Karzai to hold elections and smoothing over tensions with Pakistani officials (in the days when there was still something to smooth). Third, Obama owes Kerry something. It was Kerry who chose Obama to give the keynote address at the 2004 Democratic Convention, the address that catapulted him from Illinois state senator to superstar. Kerry asked for the job of chief diplomat after Obama was elected in 2008; when Clinton was picked instead (a move that stunned him), he settled back into his job and, among other things, did yeoman’s work steering Obama’s New START nuclear arms treaty through the Senate—no easy task, since ratification required a two-thirds majority. …

If Rice does get the job, is it a good idea to send Kerry to the Pentagon instead? Probably not. Some of his former aides, who otherwise admire him, complain of his incompetence at running a Senate committee staff, much less a gigantic executive-branch department. He has never been known for crisp decisiveness. A secretary of state can get away with these shortcomings and still do well, as the main job is to serve as the president’s adviser and envoy to the world. A secretary of defense has to do that while also shaping a half-trillion-dollar budget and imposing coherent civilian authority on the Joint Chiefs of Staff and a far flung military bureaucracy.