The evidence also suggests that immigration of low-skilled workers to the United States has a modestly negative effect on the wages of American workers without a high school diploma, as shown, for instance, in research by George Borjas, a Harvard economics professor. Yet that same immigration greatly benefits those who move to wealthy countries like the United States. (It probably also helps top American earners, who can hire household and child-care workers at cheaper prices.) Again, income inequality within the nation may rise but global inequality probably declines, especially if the new arrivals send money back home.

From a narrowly nationalist point of view, these developments may not be auspicious for the United States. But that narrow viewpoint is the main problem. We have evolved a political debate where essentially nationalistic concerns have been hiding behind the gentler cloak of egalitarianism. To clear up this confusion, one recommendation would be to preface all discussions of inequality with a reminder that global inequality has been falling and that, in this regard, the world is headed in a fundamentally better direction.

The message from groups like Occupy Wall Street has been that inequality is up and that capitalism is failing us. A more correct and nuanced message is this: Although significant economic problems remain, we have been living in equalizing times for the world — a change that has been largely for the good. That may not make for convincing sloganeering, but it’s the truth.

A common view is that high and rising inequality within nations brings political trouble, maybe through violence or even revolution. So one might argue that a nationalistic perspective is important. But it’s hardly obvious that such predictions of political turmoil are true, especially for aging societies like the United States that are showing falling rates of crime.