Pick your problem: Unemployment or income inequality
It's increasingly clear that the organizing economic concern of the American left is - or is becoming - income inequality. It's the issue that led protestors to occupy New York's Zuccotti Park in 2011. It's the anxiety that powered Bill de Blasio's campaign for mayor of New York. Last week, President Barack Obama called it - and the decline in social mobility it heralds - "the defining challenge of our time."