It takes time – or ought to, anyway – to amass the policy gravitas and political chops required to function effectively at the cabinet level. It’s not typically a young man’s job. It helps to have moved up the political ladder in previous administrations. Which might have been a challenge for the Obama transition team, had not Bill Clinton’s eight years in the White House interrupted 28 years of Republican leadership on either side. It helps to explain why we’re seeing so many familiar faces from the old days.
It does come with a downside, however: Character references.
Maybe Leon Panetta will do a better job at CIA than Clinton-era holdover George Tenet did – it’d be hard to do worse. But I bet he privately wishes that Sandy Berger could keep opinions on his qualifications to himself.