In an attempt to reduce the potential for election fraud, many states have enacted legislation that requires a valid photo ID to be presented in order to receive a ballot. According to supporters of these laws, the photo ID requirement will help prevent "Al Capone syndrome" (vote early and vote often) and will prevent votes from people who shouldn't be voting from "disenfranchising" legal voters by "canceling" out their legal vote.
Opponents object to photo ID requirements because the process of obtaining a photo ID could be burdensome to many people who are elderly or unable to drive and therefore lack a driver's license that most Americans use for a photo ID. Another objection that has been upheld in some courts is that requirement of a photo ID effectively acts as a "poll tax" since either the cost of the ID itself or the "cost" of spending the time to get it essentially charges voters to obtain a ballot.
The real fraud behind the voter ID issue is the fixation on the issue itself as the biggest problem in elections. First, the language about "disenfranchising" legal voters by having illegal votes "cancel" legal votes is telling. For me to view someone else as "canceling" my vote, I have to assume they are voting for the opposite candidate or position than I on the ballot. Statistically, if those casting the illicit ballots were spread evenly across the political / social / ethnic / financial spectrum, the "error" induced in the election results by the extra fraudulent ballots would essentially average out to zero, or, stated more accurately, average out to the larger intent of the voting public in that particular election for that candidate or issue. In reality, the largest percentage of legitimate voters lacking a photo ID are the poor and the elderly poor who are not likely to vote in equal percentages across the political spectrum.
A more subtle fallacy about the value of photo IDs in reducing election fraud involves the idea that photo IDs ensure a one to one correlation between a valid, legal voter and a clean ballot entering the tabulation system, ensuring no party or group can stuff the ballot box. The obvious flaw in this logic is that many new electronic voting machines being deployed throughout the country lack ANY verifiable audit trail for a ballot between the voter's selections in the polling place and the final tabulation. As a result, someone bent on tilting an election doesn't have to focus on "stuffing the ballot box" at the front end with illegal ballots that will then be accurately counted in their favor. Instead, they could focus on hacking the tabulation process and in many locales, NO ONE would be able to identify or prove the corrupted counts.
So where is the real risk to election integrity? The potential for a few percent of the vote total to have been fraudulently CAST or the potential for ALL of the votes to be mis-counted due to fraud or software errors with ZERO ability to audit the process? It is interesting that many of those fixated on photo IDs as the solution to voter fraud seem to have no qualms about the documented flaws in electronic voting systems being deployed throughout the country.