Why Does Charles Lane Contrast Pro-Growth Policies With Reducing Inequality?

Charles Lane used his Washington Post column today to imply that the presidential election will be a contrast between Mitt Romney pushing pro-growth policies and President Obama trumpeting reduced inequality. While Mitt Romney's campaign will undoubtedly describe the choice in this manner, what possible basis is there for someone not on Romney's payroll to frame the choice this way?

There is no clear trade-off between growth and inequality either internationally or in recent U.S. history...