Switzerland was voting in a referendum Sunday on limiting its population size – a proposal driven by divisions over immigration that could, if approved, set the country on a collision course with the European Union.

The Swiss People's Party, with the most seats in Parliament, doesn't like immigrants and wants to limit the country to 10 million people.

Right-wing SVP proposal would limit Switzerland to 10 million residents by 2050, forcing major immigration curbs and threatening EU free-movement deals

Switzerland is set to vote on a controversial anti-immigration proposal aimed at capping its population below 10 million. The hard-right Swiss People's Party initiative faces…