Brexit 2: Switzerland to vote on population cap – is it about immigration?

CNN reports that Switzerland will vote tomorrow on a proposal to cap its population at 10 million people. The

"referendum that has become one of Europe’s most closely watched tests of public attitudes toward immigration, national identity and economic growth. . . . The initiative, backed by the right-wing Swiss People’s Party (SVP), would require the government to take action if the country’s population exceeds 10 million, including potentially ending Switzerland’s agreement with the European Union on the free movement of people."

Update (June 15): Swiss voters rejected the population cap by a 55-45% margin.