How many voters does it take to make a majority? Why Ohio's Issue 1 is controversial

Ohio residents line up to vote early in-person on Issue 1 in front of the Franklin County Board of Elections in Columbus, Ohio, on Thursday. (Samantha Hendrickson/AP)

COLUMBUS, Ohio — Voters head to the polls Tuesday for a special election over Issue 1, a ballot measure which seeks to raise the threshold for voter approval of amendments to Ohio's constitution.

If passed, the measure would require 60% approval to pass future constitutional amendments, up from the current simple majority requirement that has been Ohio's standard since 1912.