Voters shifting away from the two-party system

U.S. voters have historically stuck with two political parties, but that’s changing in some states. USAFacts shows the shifts through voter registrations.

Colorado shows the first pattern most clearly. In 2016, the two major parties were nearly tied at around 30% of registered voters each, with unaffiliated voters already slightly ahead at 38%. By early 2026, more than half of Colorado’s registered voters belonged to neither major party.

This is a nice combination of ternary plots and connected scatterplots, with a bit of animation for good measure. [Thanks, Amber]