Ever since the Freedom Riders risked their lives to register black voters in the South, increasing voter registration has been an abiding liberal cause. The first great victory was the Voting Rights Act of 1965, which eliminated blatantly racist barriers such as poll taxes and literacy tests. But many other banal obstacles long remained. Well into the 1990s, if you wanted to sign up to vote in many parts of the country, you had to go to the county election commission office, present one or more forms of ID, fill out a form, and have it stamped by a notary public.
These bureaucratic hurdles disproportionately depressed registration by the poor, the young, and minorities--groups that generally favor the Democratic Party. Eager to boost participation by these groups, and to stem a general decline in turnout, in 1993 the Democratic-controlled Congress passed, and President Bill Clinton signed, the National Voter Registration Act (NVRA). Dubbed the "motor voter" law, it mandated, among other things, that states offer citizens a chance to register by mail or whenever they go to the DMV or other government agencies.
Despite a certain amount of foot dragging by some states, the NVRA generally worked. The share of voting-age citizens registered to vote rose from less than 75 percent in 1994 to more than 85 percent in 2012. Most states now let residents register online. Some state GOP election officials tried to roll back the law's gains by, for instance, aggressively purging names from the registration rolls on the pretext of fighting voter fraud. But the courts have consistently blocked their actions as violations of the NVRA. (A key case involving voter purges in Ohio is now before the U.S. Supreme Court.) Today, it has never been easier in America to register to vote, and there have never been more Americans registered.
But if the ultimate aim was to boost the number of citizens who actually cast ballots, it's hard to say that the law has been a big success. Numerous studies have tried to measure the effect of the NVRA on turnout. Few have found any clear impact. That doesn't mean there has been none; turnout declines might have been worse without the NVRA, and in any event data limitations make it hard to prove causal connections. But based on the evidence so far, the law seems mostly to have added to the substantial pool of citizens who are registered but don't bother to vote.
This fact has not dimmed enthusiasm for voter registration among...