In 2008, the United States suffered the worst financial crash since 1929. It was followed by the worst downturn since the Great Depression. Big banks, which had bent the law to reap millions, were widely seen to have precipitated the calamity. And the super-rich, in turn, have been the big winners in the recovery: Labor participation has been at record lows and workers’ wages are lagging, yet the income of the top one percent has continued to skyrocket: According to University of California economist Emanuel Saez, it shot up 31.4 percent from 2009 to 2012.

It’s not news that most Americans are troubled by this growing gap. Two vocal critics of inequality, Elizabeth Warren and Thomas Piketty, have become rock stars in the past couple years. Occupy Wall Street commanded attention, and commandeered a chunk of lower Manhattan, during the fall of 2011. And Barack Obama rode to a surprisingly easy reelection by painting Mitt Romney as an apologist for the wealthy. In a Pew poll last January, 66 percent of people, including 61 percent of Republicans, agreed that there is a “growing gap between the rich and everyone else.” Sixty percent agreed and only 36 percent disagreed that “the economic system in this country unfairly favors the wealthy.”

The surprising thing, though, is just how limited the backlash has been. Public alarm about economic inequality could have sparked the sort of tumult that buffeted American politics in the late 19th century and again during the 1930s. But a powerful movement has not emerged. Warren and Piketty remain well outside the mainstream. Occupy Wall Street petered out after a few months. And after coasting to victory as a foe of plutocracy, Obama couldn’t even win support ending the tax loopholes that benefit hedge fund operators—or for a mere hike in the minimum wage. Republicans, generously funded by business leaders eager to roll back regulations on corporations and taxes on the wealthy, are poised to win control of the Senate in November.

Why did movements against economic inequality flourish in the past, but not now? Some people on the left blame the President. If only Obama had taken a stronger stand against what Theodore Roosevelt called “the malefactors of great wealth,” the logic goes, he could have roused the country to action and prevented the rise of the Tea Party. That argument seemed persuasive to me four years ago, but no longer. If you compare the circumstances in which the older challenges to inequality took place with those now, you discover that something important has been missing and would have been missing regardless of whether Obama had sounded the tocsin. For all the talk today about stagnant wages and the long-term unemployed, today’s foot soldiers of a movement remain significantly more invested in the status quo than those who embraced populist agitators Sockless Jerry Simpson or Huey Long.

There have been two great movements against economic inequality in American history: One was led by the populists, socialists, and progressives of the late nineteenth and early twentieth centuries. The other featured the populists, socialists, and liberals of the 1930s. Both took place during sharp economic downturns—the farm crises and depression of the 1880 and 90s, and the Great Depression of the 1930s. These upsurges didn’t originate out of resentment or envy of the rich, but out of the belief that the wealthy, through their actions, had precipitated the downturns. The movements demanded and got, among other things, a progressive income and inheritance tax, banking and railroad regulation, government support for collective bargaining, social security, unemployment compensation, and a minimum wage.