Both President Obama and Republican presidential candidate Herman Cain went to graduate school. Obama got a degree at Harvard Law School. Cain did his graduate work at Purdue and Burger King University. That doesn’t tell you all you need to know about the difference between Obama and Cain, but it explains a lot. Obama and Cain are African Americans, but there the likeness ends. Obama is a liberal, Cain a conservative. Their parents, their upbringing, their education, their careers, the lessons they learned from life—these are as dissimilar as where they’ve wound up, Obama in the White House and Cain...