Why are partisan differences so sharp and bitter in America today? It’s a question many have been asking and trying to answer. On the Washington Post’s Monkey Cage blog, University of Maryland political scientist Frances Lee gives an interesting explanation: It’s because American politics these days — which is to say, over the last 20-some years — has become very competitive, more so than at most times in American history. “Competition for power,” writes Lee, “not only ideological polarization, contributes to our confrontational politics.”
Lee illustrates her proposition with a graphic showing an Index of Two-Party Competition in every decade from the 1860s to the still-far-from-complete 2010s. There are decades of substantial one-party dominance: the Civil War 1860s for the Republicans (when the mostly Democratic South usually wasn’t voting) and the Great Depression 1930s for the Democrats. Republicans also had significant dominance in the 1900s and 1920s. The five decades after the Depression — the 1940s, 1950s, 1960s, 1970s and 1980s — showed varying degrees of Democratic dominance.
