The Heritage Foundation is a think tank, not a primary source. Do you know of any primary sources?
The article you linked to talks about election fraud (i.e. the rigging of an election), not voter fraud (i.e. a ballot voted by one who is ineligible to vote).
The article you linked to talks about election fraud (i.e. the rigging of an election), not voter fraud (i.e. a ballot voted by one who is ineligible to vote).