Election Fraud.

 Election fraud denies the benefit of elections to people who have the right to vote. If a person properly casts a vote for a given candidate or proposal and someone else casts an illegal vote in opposition, the legal vote is effectively canceled. 

There is an irreconcilable trade-off between access to voting and prevention of fraud. Constant complaints of abstract voter suppression ignore this fact. Addressing this circumstance dismissively by saying that there is "no evidence" of voter fraud enables voter fraud. 

It is more important that legitimate votes be protected against cancelation by fraudulent votes than it is that elections accommodate a theoretical class of people who are assumed to be unable to comply with even the most basic of voter requirements.