The United States prides itself on the belief that “anyone can be president,” and what better example than Barack Obama, son of a black Kenyan immigrant and a white American mother — neither of them rich.

And yet more than half the presidents over the past 110 years attended Harvard, Yale or Princeton and graduates of Harvard and Yale have had a lock on the White House for the last 23 years, across four presidencies. Thus we have become both more inclusive and more elitist.

Inequality has traditionally been acceptable to Americans if accompanied by mobility. But most recent studies of economic mobility indicate that it is getting even harder for people to jump from one economic class to another in the United States, harder to join the elite. While Americans are used to considering equal opportunity and equality of condition as separate issues, they may need to reconsider. In an era in which money translates into political power, there is a growing feeling, on both left and right, that special interests have their way in Washington. There is growing anger, from the Tea Party to Occupy Wall Street, that the current system is stacked against ordinary citizens. Suddenly, as in the 1930s, the issue of economic equality is back in play.