Well, well. Hot on the heels of the English translation of Thomas Piketty’s magnum opus comes this report of a new study by Martin Gilens and Benjamin Page from Princeton. Excerpt:

Money buys power.

That’s the bottom line of a new study from Princeton University political scientist Martin Gilens, who looked at 1,779 U.S. government policy decisions between 1981 and 2002. Gilens found that the preferences of the median earner had no impact on whether policies are adopted — but that politicians march in lockstep with what the top earners wanted.

You may think you’ve heard that conclusion before, but Gilens’s approach is unique, and that makes his findings all the more important. Gilens didn’t take one theory of who has political influence and test it with data, as does almost all of the research on this topic. He tested the power of the rich, middle class, and interest groups simultaneously, allowing for any theory to win or lose. That is new.

And here’s the real danger of what Gilens finds: It means that the U.S. political system is set to transform the dramatic rise of income inequality into entrenched differences in political power — and there’s very little the middle class can do to stop it from happening.

There is, in other words, an inequality feedback loop built into the U.S. political system — and America may be spiraling into it. A policy that enriches what Gilens calls the “economic elite” will command its support. Their support, Gilens shows, means that the political system is likely to make it happen. And the ever wealthier become the ever-more powerful. Policies that undermine the elite become ever more difficult to pass as economic inequality buys political obedience.