According to U.S. census data crunched by Atlantic Cities, Minnesota congresswoman Michele Bachmann, the toast of the tea party, represents the district with the lowest level of income inequality in the country. Inequality is highest in the New York City district of Rep. Jerry Nadler, a liberal Democrat. Those extremes reflect a partisan divide: Across the country, inequality is lower in Republican districts than in Democratic ones.

That's not surprising, given that high levels of wealth and poverty — and thus inequality — tend to be concentrated in cities dominated by Democrats. But it does call into question the political wisdom of the Democratic Party's effort to make income inequality the centerpiece of its national economic agenda.

This November, control of the U.S. House will not be determined by voters in safely Democratic major cities, but by voters in suburban and rural districts, where inequality tends to be lower. And control of the Senate will be decided largely in states with low levels of inequality relative to the national average.