"Referendums should be illegal."
Just like the states require licensed drivers to first pass a written road laws test, the states should require everybody to first pass a state and federal constitutions voter's qualification test before being allowed to vote.
In fact, local schools should make passing state and federal constitutions tests a requirement for graduating from high school and enrolling in college.
That can never happen, because this idea is too reminiscent of the old literacy tests administered in the old South, to keep black people from voting.