Using data collected by Amlani and Algara (2021), I wanted to explore how US politics have become increasingly nationalized. One way to see this is looking at county-level correlations in vote choice: in recent years, the correlation between counties' Democratic voteshare for president and their Democratic voteshare for senate has grown increasingly strong, and is now (as of 2020) nearly 1.
Check out this Bokeh tool to dig into historical county-level results in detail.