Ideological Extremists in the U.S. Congress: Out of Step but Still in Office

In the last generation, congressional moderates have become ideologically more extreme over the course of their careers. We explain this "ideological migration" of moderates as a side effect of close partisan competition for control of the US House since 1994. Competition for the House caused activists, donors and, indirectly, voters to focus on the battle for majority status. Increased attention to partisan competition reduced individual members' ability to escape blame for their parties' actions. Equivalently, it meant that members could deviate from their district preferences and pay a lower electoral penalty; they would be blamed in any event. Our empirical analysis shows that party-centeredness abruptly and dramatically increased after 1994, with the electoral penalty members paid for being out of step with their constituents correspondingly declining. This contributed to an important, albeit complicated, shift from local/personal to national/party representation.