On Monday, the Justice Department blocked implementation of Texas' new voter identification law. Texas said the law is a necessary measure to prevent voter fraud. Justice responded that the law is unnecessary and will have a disproportionate impact on Hispanic voters who are less likely to have identification. The issue is heading to federal court, and it could well be the U.S. Supreme Court that weighs in, just months after it intervened in Texas's redistricting dispute.So who's right? As I explain in The Fraudulent Fraud Squad sneak preview of my forthcoming book The Voting Wars, Republican claims of a serious problem with voter impersonation are bogus. Many Republican legislators and political operatives support voter ID laws for two purposes: first, to depress Democratic turnout, and second to gin up the Republican base. But Democrats and those on the left sometimes inflate the potential negative effect of voter identification and other laws on voter turnout, especially among poor and minority voters. Just as Republicans use the scare of voter ID laws as a wedge issue to boost Republican turnout, Democrats use the scare of voter suppression to boost Democratic turnout.Given the exaggeration on both sides, one might be tempted to say that there's not much harm in the laws and so they should stand. I disagree, for four reasons.First, these tough new voter ID laws serve no purpose. Of course, some identification requirement is necessary to prevent voter fraud. But many states use signature matches or other tools (including the ability to have witnesses verify identity) besides a state photographic identification requirement. Further, the federal Help America Vote Act requires first-time voters anywhere in the country who register first by mail to provide identifying information.There is no good evidence that impersonation voter fraud, the only kind of voter fraud an ID law can prevent, is a real problem. Impersonation fraud would be an exceedingly dumb way to try to steal an election because you would need a lot of people, could not verify how they voted, and they could easily be caught. People are prosecuted all the time for other kinds of voter fraud that do work, like manipulating absentee ballots.Second, many Republican legislators support them for the wrong reason. Texas passed its law along party lines after Democrats fought the effort for years. A few years ago, state Sen. Mario Gallegos, recovering from complications of liver surgery, had to be wheeled into the Texas Capitol from a hospital bed to block the law. Both Republicans and Democrats view voter ID not as an anti-fraud measure but as a way to help Republicans at the polls.Third, even if the effects of voter ID are small, they can still matter in razor-thin elections. Perhaps voter ID laws deter about 1 percent of voters from voting (and more who forget their IDs and don't return to vote again -- a real concern for Democrats about low-motivation voters). One percent may not seem like much, but we have had enough razor-thin elections in recent years that some elections could well turn on such a small effect. Further, we don't know if Texas' new, very strict law -- including a provision barring the use of student IDs -- will have a larger effect.Finally, even when effects of ID laws are too small to affect the outcome of elections, we should not make it harder for people to vote for no good reason. Everyone entitled to vote should be able to vote; we should not put stumbling blocks in front of voters to solve a nonexistent problem.Richard L. Hasen is a professor of law and political science at the University of California, Irvine School of Law and author of "The Voting Wars: From Florida 2000 to the Next Election Meltdown." He also writes the Election Law Blog, electionlawblog.org.