Timothy Geithner has said that he'll step down as Treasury Secretary at the end of Obama's first term. Assuming that Mitt Romney keeps self-destructing and Obama wins a second term, who should succeed him? Just as Obama's choice in 2008 of an economic team led by Larry Summers and Tim Geithner told you a lot about what kind of president he'd be (and not be), Obama will signal a lot in his selection of Geithner's replacement. In an economic crisis, the treasury secretary (tied with the Fed chairman) becomes the most important domestic public official after the president.