The job of treasury secretary is arguably the most important one the president will fill in his second term. It's certainly the choice that will most affect the American people's daily lives, future hopes, and aspirations.
It would be hard to find a Washington political insider with greater power and fewer enemies than Jack Lew, who's moving over from the OMB directorship, which he's occupied twice, to become the White House chief of staff.
Obama once told a meeting of bankers that he was "the only thing standing between you and the pitchforks." Picking Daley sends the message that pitchforks ("normal people") matter less than the uber-wealthy.