While you must be a U.S. citizen to vote in American elections, most states allow those wishing to register to simply sign a statement affirming they are citizens and provide a driver’s license number, Social Security number, or other proof of residency.
A Reuters analysis of the Kansas suspense list shows the law disproportionately hits young voters, who often do not have ready access to the needed documents, as well as unaffiliated and Democratic voters in the Republican-controlled state.