It may be an off-year election cycle, but the November ballot initiatives are heating up. One particular fight is fundamental to our democracy: citizen-only voting.

Most people assume that to vote in the United States, one must be a U.S. citizen. But this is not the case: Only 20 state constitutions include language explicitly confirming that only U.S. citizens are allowed to vote in elections. Every other state is vulnerable to cities allowing noncitizens to vote.