Visualizing the US congress

I present an interactive visualization for the US Congress members' ideology. The data used are ideology scores of US Congress members 1789-2015. The ideology scores are quantified from the Congress members' voting records using the DW-NOMINATE method, which puts Congress members with similar voting patterns closer together. This interactive visualization shows a clear picture of the polarization in the US Congress over time, and offers a platform for people to explore the history of ideology changes in congress.