Our political system is so plagued by polarization, it’s difficult to move any legislation forward. In the late 1960s, significant overlap existed in votes cast by the most conservative Democrats in Congress and those cast by the most liberal Republicans. (See accompanying chart: Polarization in Congress.) By the late 1980s, the common ground had diminished. Today, it has virtually disappeared.
What’s causing this? Many people have said the problem is that Congressional districts have been redrawn to be as partisan as they can be, to keep politicians from each party in office as long as possible. (Optimizing the district lines in this manner is a harder problem than it may initially seem, as research by two Harvard economists has shown.) Thomas Friedman, the New York Times columnist, for one, has blamed “the gerrymandering of political districts,” which made each one permanently Republican or Democratic, for “erasing the political middle.”