"Over the past three years, Barack Obama has been replacing our merit-based society with an Entitlement Society," Mitt Romney wrote in USA Today last month. The coming election, Romney told Wall Street Journal editors last month, will be "a very simple choice" between Obama's "European social democratic" vision and "a merit-based opportunity society — an American-style society — where people earn their rewards based on their education, their work, their willingness to take risks and their dreams."

Romney's assertions are the centerpiece of his, and his party's, critique not just of Obama but of American liberalism generally. But they fail to explain how and why the American economy has declined the past few decades — in good part because they betray no awareness that Europe's social democracies now fit the description of "merit-based opportunity societies" much more than ours does.

The best way to measure a nation's merit-based status is to look at its intergenerational economic mobility: Do children move up and down the economic ladder based on their own abilities, or does their economic standing simply replicate their parents'? Sadly, as the American middle class has thinned out over recent decades, the idea of America as the land of opportunity has become a farce. As a paper by Julia Isaacs of the Brookings Institution has shown, sons' earnings approximate those of their fathers about three times more frequently in the United States than they do in Denmark, Norway and Finland, and about 1½ times more frequently than they do in Germany. The European social democracies — where taxes, entitlements and the rate of unionization greatly exceed America's — are demonstrably more merit-based than the United States.