There's a principle in poker that says it is best to determine what your opponent wants you to do, then disappoint him. This very neatly explains why Obama did not choose Hillary for his VP running mate. Simply put, the Republicans wanted Hillary.They have 16 years' worth of material worked up on how to take her down and that's just counting her national presence since 1992. It's high time the Democrats stop giving the Republicans what they want.
It's true in poker, and it's true in politics: disappoint your opponent, win the battle.