Voter fraud needs to be defined for the various debaters. Voter fraud does exist, however not in large enough numbers to affect the outcome of elections.
I've "debated" with people who believe it exists, and it came to light that, in their mind, ANY voter fraud, no matter how insignificant, is a problem. Their take was that if one fraudulent vote was found, the whole election should be a redo! I had to laugh as their naivety showed they had no idea what it take$ to run an election.
In the US voter fraud is virtually nonexistent in large enough numbers to affect an elections outcome. In that sense it is a myth.