The United States Senate composition and competitiveness

This is an abridged version featuring highlights of a recent analysis refuting claims by Norman Ornstein and others that the Senate is and will become rigged for Republicans on the basis of population, race, sex or age. The data is based on the current composition of the U.S. Senate, Census data and Senate history.

Note that this is not incompatible with the fact that the Senate’s equal representation of states purposefully inflates the voting power of less populous states.

Bottom line: Republicans win where one would expect — small states and white states — but they maintain their Senate advantage by leading or remaining competitive in larger, less white, less male and younger states.

Important reminder: Senators are elected to represent the state — not the people or the country. The House of Representatives is elected to represent the people.

Other points:

  • Contrary to stereotypes, the younger the average age of the state the more likely it is to be represented by Republican senators.
  • Republicans perform better in states with higher proportions of white Americans and where the proportion of men to women is higher.
  • Democrats perform better in states where the proportion of men to women is lower and where the average age of the population is older.
  • The starkest victory margins based on these demographics is age. Democrats hold a 6-seat advantage in the oldest quartile of states. Republicans hold an 8-seat advantage in the youngest quartile. Both parties virtually split states in between.
  • In Figure 5, the states are loosely cross-ranked based on the population, proportion of white Americans, male-to-female ratio and age. The higher the rank the more stereotypically Republican the state is (that is, collectively smaller, whiter, more male and older). Republicans hold a 4-seat advantage in the top-quartile. They hold a 1-seat advantage in the least stereotypically Republican states.
  • In the most stereotypically Republican quartile of states, Democrats have won a Senate seat in 6 of those 12 states within the last 12 years — more than in any other quartile.
  • Since 2000, the number of seats Democrats have won in states that are currently represented by two Republicans is 12. Since 2000, the number of seats Republicans have won in states that are currently represented by two Democrats is 10.
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