The supercommittee’s failure to reach a substantial agreement this week is disappointing but unsurprising. The old model of politics, in which bipartisan agreement was the key to success, simply doesn’t work anymore. In the new model, there is almost no overlap in views across party lines, and government function requires either domination by one party (as was the case for much of President Barack Obama’s first two years in office) or more automatic decision-making (as I have suggested elsewhere).
What’s causing today’s hyper-polarization? Although political scientists still debate the issue, a growing body of evidence suggests that, as economists such as Paul Krugman and Ed Glaeser have argued, increases in income inequality may play a significant role.
It is striking that both income inequality and political polarization began to rise sharply in the U.S. in the mid- to late 1970s. Yet many pundits airily dismiss this connection, arguing that because blue states are, on average, higher-income than red states, the link between income and partisanship must be weak. Instead, they attribute increasing political polarization to the gerrymandering of legislative districts. Both of these assertions are empirically false.
Gerrymandering plays a relatively modest role in polarization trends. A more plausible driver is the sorting of the population itself into effectively two different camps. To a stunning degree, Americans are increasingly moving into neighborhoods with other people who have similar incomes and share their political views.