Pundits have long warned that politics has grown more polarized. Politicians are now far less willing to forge compromises, or even friendships, across the aisle. Cooperation, those commentators claim, has all but disappeared.

Now, a study shows that political polarization may have even more serious consequences that affect more than just the workings of Congress.

The study, conducted by Federal Reserve Bank of New York economist Rajashri Chakrabarti and researcher Matt Mazewski, found that political polarization and income inequality are strongly correlated. As Republicans and Democrats have grown apart, so too has the gulf between the wealthy and the middle class.


When the authors mapped income inequality on top of political polarization, the trajectories looked remarkably similar, with inequality lagging behind polarization by about five years.

According to the study results, polarization has grown since the 1970s and has now reached its zenith. Since inequality seems to lag behind polarization, we may see inequality continue over the next few years to catch up with political polarization.

The authors noted that polarization is not associated with the growth of the economy, given that GDP growth bore no resemblance to partisanship trends.

They instead honed in on the share of the economy controlled by the richest 1 percent of Americans. That share, they found, was highly correlated with political polarization.

The study, which was released Monday, used Congressional roll call votes dating back to the Civil War to measure just how polarized parties were. The authors also looked at the so-called “Gini Coefficient,’’ a measure of inequality, to measure the gulf between the highest 1 percent and average Americans.

The correlation between inequality and polarization was far stronger when the authors looked at roll call votes in the House compared to the Senate.