The Proportional House — mapping the U.S. House under proportional representation.
An interactive model of the U.S. House: set the national vote margin, add third parties, switch the allocation method (Pure PR, multi-member districts, or MMP), impose an electoral threshold, and resize the chamber beyond 435 seats — every seat count recomputes live.
This interactive site requires JavaScript. The data is public:
projection.json, the
v1 API, and static per-state pages under /state/.