As Thomas Frank points out in his Listen Liberal, loc 811-828, calls for more centrism have long followed the defeat of Democrat centrists:
Democrats would run for the presidency on a professional-friendly platform of high-minded post-partisanship and be rejected by the electorate—and then, in the aftermath, those same Democrats would be ritually denounced by Washington’s TV thinkers as examples of the New Deal’s exhaustion and irrelevance. It happened to the post-ideological Jimmy Carter in his bid for reelection; it happened to the budget-balancing Walter Mondale; it happened to the technocratic centrist Michael Dukakis—each one of them magically transformed on the day of their defeat into an instructional film on why Democrats needed to embrace post-ideological, budget-balancing, technocratic centrism.
