(e) Presidential vote closely reflects voters’ party loyalties and is not influenced by whether an incumbent is running in a district or how much money the local candidates spend. (+) Districts that voted at least 10 percentage points more Democratic than the nation were classified as safe Democratic; districts that voted at least 10 percentage points more Republican than the nation were classified as safe Republican; districts that were within 5 percentage points of the nation were classified as competitive.
(a) House district have become less competitive, but not because of redistricting. Most of the change has occurred between redistricting cycles. For the same reasons that states and counties have become less competitive- Americans are increasingly voting for candidates who reflect those values. (e) on the county level-number of counties dominated by one party and the proportion of voters living in such counties have increased dramatically over the several past decades. Also, growing ideological polarization at the elite level has made it easier for voters to choose a party identification on the basis of their ideological preferences. (+) Polarization=sorting, as voters bring their policy and partisan preferences into alignment
(a)Growing financial advantage enjoyed by incumbents also contributes to the low level of competition in recent congressional elections. (e) It now costs over a million dollars to wage a competitive campaign for a U.S. House seat. (+) Most incumbents can raise that kind of money easily, but very few challengers can (they lack the financial resources needed to wage competitive campaigns). The most vulnerable- those in districts that were more supportive of the opposing party’s presidential candidate than the nation.
Claims that redistricting does have an effect on the number of competitive congressional districts and, as a case study of redistricting institutions in Arizona illustrates, the choice of redistricting