The State Similarity Index attempts to quantify how similar states are to each other relative to other states. The index is a statistically-based way to measure this. 20% of the index is based on politics. 16.66% of a state’s political score (3.33% of the overall State Similarity Index score) is based on the state’s legislative branch preferences, both in the US Congress and the state’s legislature. States were compared according to their percentage of Democrats, Republicans, and Independents.
US Senate Election
There are two senators per state. The party of the state senators is highly correlated with which presidential candidate the state chooses, although there are exceptions. In recent times, West Virginia has been one of the easiest Republican victories for presidential candidates, however from 1958 to 2014, both senators from West Virginia were Democrats. Recently Montana also had an 8 year period of having two Democratic senators, despite always voting for Republican presidential candidates. Maine is the opposite. It has not had a Democratic senator since 1995, despite voting for the Democratic presidential candidate in every election since then.
Source: 270 to win (data as of 2020)
Categories: Democrat, Republican, Independent
US House of Representatives Election
Since most states have more congressmen in the House of Representatives and their races are not state-wide, their political party has less correlation with the presidential election. Although Minnesota is one of the Democratic strongholds in the presidential race, the state’s representatives in the US Congress are closely split between Republicans and Democrats. Michigan is another Midwestern state with this characteristic. Texas is an example of a state where Democrats rarely win a state wide election, yet a large portion of their representatives in the house are indeed Democrats.
Source: 270 to win (data as of 2020)
Categories: Democrat, Republican, Independent
State Senate Election
The State Senates of Hawaii, Massachusetts, and Rhode Island are the most heavily Democratic in the country. Over 75% of their state senators are part of the Democratic Party. This is in part due to the fact that even the people living in the rural areas of these states are not conservative. The State Senates of South Dakota and Wyoming are the most heavily Republican in the country. They are primarily rural. Sioux Falls, the largest city in either state has less than 200,000 residents.
Source: 270 to win (data as of 2020)
Categories: Democrat, Republican, Independent
State House of Representatives Election
Generally, the political party composition of the state senates closely aligns with that of the house of representatives. Nebraska is the only state that has a unicameral legislature, so it only has state senators. Vermont has the highest percentage of independents, but they still amount to less than 25% of their state’s legislators. However, the exact political composition of legislatures varies each year.
Source: 270 to win (data as of 2020)
Categories: Democrat, Republican, Independent
