This is an interesting thought from Matthew Yglesias:
With Richard Daley apparently ready to relinquish his long-held post of Mayor of Chicago, it’s worth reflecting on the slight oddness of the American idea that the next Mayor of Chicago should be some other politician who happens to be from Chicago rather than some other mayor who’s done a good job. They’re going to get some Alderman or maybe a member of the US House of Representatives or maybe Rahm Emanuel. My understanding of how they do this in China is that they’d promote the mayor of some other city.
Obviously the rationale for this norm is that you want a mayor who knows the particularities of the city he or she is taking over -- though we don't insist on this familiarity when we’re hiring police chiefs, school superintendents etc. Probaby more relevant than the rationale, though, are the realities of politics – it’s tough to get elected as an out-of-towner. You have no constituency, no name recognition, no one people know and trust who can vouch for you to other voters. But just because there's an explanation for this norm doesn't mean it serves us well. We'd be curious to hear what people think about this.