With an increasingly polarized Congress and fewer competitive elections, there are growing calls among some election reformers to change how voters elect members of the U.S. House of Representatives.

For most Americans, voting for a member of Congress is one of their simplest civic duties. Every two years, they pick the candidate they like best—usually the same one they chose last time—and whoever ...

California’s congressional districts, like most across the country, operate under a winner-take-all, single-member model.