and Candidate Competition in U.S. House Elections

Research on candidate competition has focused on how much context matters in emergence decisions and election outcomes. If a candidate has previously held elected office, one additional consideration that may influence entry decisions is the relative degree of overlap between the candidate’s current constituency and the “new ” set of voters she is seeking to represent. Using GIS software, we derive a measure of the challenger’s personal vote by focusing on constituency congruency between state legis-lative and congressional districts. Results suggest state legislators are more likely to run for a seat in the U.S. House if constituency congruency is relatively high. In 2004, Democrat Jim Costa and Republican Roy Ashburn emerged to run for the open seat in California’s 20th District in the U.S. House of Representatives. Although we can label Costa and Ashburn “quality ” challengers due to their prior service in the California State Senate (Jacobson 2009), Costa possessed an additional advantage over Ashburn from the outset. As a state senator, Costa had already repre-sented 98.7 % of the constituents who lived in the House district he was hoping to win. Ashburn’s senate district, on the other hand, only shared 0.3 % of the same geographic constituency. Even though both candidates spent over $1 million in this highly competitive race, it was Costa who went on to serve in the U.S. House, while Ashburn remains a California State Senator. One reason why Costa was able to win was that he only had to get the same set of voters who elected him previously for the state senate to vote for him again at the congressional level. Ashburn, in contrast, had to appeal to an almost entirely new set of constituents. This example illustrates that some candidates enjoy certain advantages (e.g.