http://www.snopes.com/politics/ballot/2012fraud.asp
When you want to disenfranchise minorities, the young, the non-English speaking, and the poor the easiest way to do it is with restrictive registration laws.
The voting fraud argument has been demonstrated continuously as a fraud in and of itself.
The Voting Fraud crowd wants restrictive voter registration. Disenfranchising a few million to eliminate a few dozen cases of fraud is insane.
Most cases of voting fraud are by election employees, not by the general public.