Diagram of Similar US State Presidential Preferences

This is an attempt to quantify how similar the presidential preferences are for American states relative to other states historically. Data from 1960 to 2020 was used, since it was the first time that all 50 states had electoral votes in the presidential election. States compared to each other based on the following criteria.

vote more than 10% in favor of Democrat candidate
vote more than 1% in favor of Democrat candidate
vote more than 0.1% in favor of Democratic candidate
vote more than 0.1% in favor of Republican candidate

vote more than 1% in favor of Republican candidate
vote more than 10% in favor of Republican candidate
vote more than 0.1% in favor of Third Party candidate
vote more than 1% in favor of Third Party candidate
vote more than 10% in favor of Third Party candidate

This data was used to cluster American states into different “presidential preference” regions.

However, it may best to look at the presidential preferences of states as a connected web, not as hierarchical clusters, since the data reveals the relationship of states to each other is more of a gradient than having clearly defined clusters. Therefore, this diagram was created to reveal more intricate linkages between states rather than simply grouping them into regions.

While many states with similar presidential preferences border each other, there are many notable exceptions on the map. Florida and Ohio are grouped together because they are fairly average states that have been favoring Republican candidates in recent years. Hawaii is grouped in with New York and Minnesota, since they heavily favor democrats. Interestingly enough, Colorado is politically located in between New Hampshire and Virginia. These states once often voted for Republicans but are now turning into strongholds for Democrats.

Hopefully, this graphic will help people better understand the political similarity of states.

Downloadable graphic:

us state politics spectrum _Download

Methodology

The logic of the connected web is as follows: each state is connected to its most similar state and also the next most politically similar state that is not more similar to the states more similar to the state. For example, the most politically similar state to Mississippi is Alabama. However, its next most similar state, South Carolina is more similar to Alabama than Mississippi. The next state that is more similar to Mississippi than Alabama is Kentucky. Therefore, Mississippi is on a spectrum somewhere between Alabama and Kentucky.

Please keep in mind that just because some states are close to each other on this graphic, does not necessarily mean they are very politically similar to each other. Only the lines connecting states are meaningful, not their location on the graphic. For example, although West Virginia and Arizona are next to each other in the graphic, no lines are between these states, so no relationship is necessarily implied. The shorter the line, the more similarities in presidential preferences between the states.