You may think that is only among developed nations, and the U.S. would look better when nations like India and China are included -- nations that Americans tend to think of as very unequal. But that would be wrong. Both of those nations are on the chart, and neither is as unequal as the United States.
This must be fixed. As inequality increases, democracy decreases -- because the greater the portion of wealth held by the rich, the easier it is for them to buy what they want from government.