As part of its Monopoly Politics 2014 analysis on polarization in Congress, FairVote found that two key factors figure prominently into how Members of Congress vote: their party and the partisanship of their districts. More specifically, the vast majority of Members tend to vote with their party on key votes. Only those who represent “swing districts” – that is, districts with a partisanship favoring their party by less than 53% – or those who represent districts that favor the other party (“crossover representatives”) have any incentive to reach across the aisle and vote with the other side. Despite their crucial role, these legislators are on the decline in Congress: now, crossover representatives comprise just 6% in the House, and only 11% of congressional districts are “swing.”
State legislatures, overall, have similarly low percentages of crossover and swing representatives. The state in the Daily Kos data with the median proportion of swing districts is Virginia, with 12%, and the state with the median proportion of crossover representatives is Hawaii, with 9%. In all 29 states surveyed, 11.6% of districts had crossover representatives.