Is Caroline Kennedy really the best choice as the next U.S. ambassador to Japan, one of America's most important allies? 

This is a job that's been held by, among others, former Senate Majority Leader Mike Mansfield, former Vice President and Senator Walter Mondale, former Speaker of the House Thomas Foley, and former Senate Majority and Minority Leader Howard Baker. With more than a century's worth of elected office between them, not for nothing were they referred to by the Japanese press as "O-Mono" -- big deals. And the guy I worked for at the Tokyo embassy in the early 1990s, Ambassador Michael Armacost, had been, among other things, an Undersecretary of State and Ambassador to the Philippines before taking the job.

To be sure, as the senior survivor of one of America's leading political dynasties, Kennedy is a big deal in her own way. And her possible appointment, news of which first surfaced a month ago, would doubtless be something of a "you go girl!" inspiration to Japanese women, who haven't exactly cracked the glass ceiling.

Kennedy's own career, however, has been mostly philanthropic and focused on U.S. issues. Unlike, say, Anna Wintour, another big-ticket Obama supporter whose name has come up for ambassadorships, she hasn't had to brass-knuckle her way to the top and fight to stay there. Instead, she's done good deeds, tended the flames of the Kennedy legacy, written books and raised millions of dollars for New York City's public schools.

This is all important and worthwhile work. It's not the same, though, as resolving a decade-long impasse over military bases, negotiating Japan's accession to one of the world's most ambitious free trade agreements, defusing potentially explosive territorial disputes or coordinating a response to North Korea, to name some of the biggest challenges facing the bilateral relationship. Professional diplomats handle most of the details in such negotiations, but the U.S.-Japan relationship is at a critical juncture that calls for seasoned inside and outside skills, something that Kennedy's limited forays into politics suggest she'd have to acquire on the job.

Moreover, Kennedy's intellectual affinities seem pretty occidental. The administration's much-touted turn to Asia would benefit more from someone who knew the region. Someone like Edwin Reischauer, the ambassador whom her father, John F. Kennedy, sent to Japan. Reischauer was a fluent Japanese speaker, a wartime analyst in U.S. military intelligence and a Harvard professor whose books on Japan and Asia became classics. He helped rebuild relations following riots over the U.S.-Japan Mutual Security Treaty of 1960. Caroline Kennedy may be a smart and wonderful person. But to borrow Lloyd Bentsen's old line, she's no Edwin Reischauer.

(James Gibney is a member of the Bloomberg View editorial board. Follow him on Twitter.)