Two ideological camps are in a bitter struggle over voter identification rules, and neither side has a lot of facts behind its arguments. Proponents of liberty should beware of one thing: If a national voter ID requirement takes hold, such a system would be cause for regret across the ideological spectrum.

It has become an article of faith among many conservatives that voter fraud is a significant problem or at least a significant threat. “Voter fraud” is what occurs when ineligible people vote or eligible people vote in more than one jurisdiction. The conservative camp believes it skews elections in favor of liberals and Democrats.

Liberals believe just as firmly that efforts to secure voting processes more tightly, such as voter ID requirements, seek to suppress the vote of their traditional constituencies. They believe that toughened voter ID laws will skew elections in favor of Republicans and conservatives.

Modern electioneering will increasingly heat the debate. Information-driven campaign techniques — sophisticated polling, “micro-targeted” messaging and get-out-the-vote efforts — allow the political parties to more finely tune their campaigns, seeking tighter victories so they can use resources more efficiently. This increases the chance that small irregularities could affect outcomes.

But a couple of broader policy efforts also stoke these fires. Increasing voter participation has been a policy fetish for the last decade or two — never mind whether more voting for its own sake makes for better democracy. The Motor Voter Law, passed in 1993, has pushed voter registration materials at new and re-registering drivers with dubious results, including increased chances of voter fraud.

The growth in absentee balloting has undone some of the protections against voter impersonation and multiple voting that previously existed. People are much more reticent to commit fraud in person — it’s riskier — so in-person voting was a natural security against impersonation fraud. Voting in multiple jurisdictions is simply too time-consuming to do on any scale when it has to be done in person.

There have been registration frauds — canvassers in big electioneering pushes have signed up anyone and everyone, the living and the dead. But proven instances of people going into polling places unqualified to vote, masquerading as others or in multiple jurisdictions have been few and far between.

Were there evidence of routine or systematic voter fraud, it might be appropriate to establish systematic measures to counter it. As in all policy decisions, the steps taken to counter occasional voter fraud or the threat of it must be balanced against their costs.

The state of Indiana instituted a strong voter ID requirement in 2005. In the Crawford vs. Marion County Election Board case argued before the Supreme Court last week, the ACLU and NAACP claim that Indiana’s voter ID requirement will disenfranchise the poor and the elderly. On the margin, it probably will, but none of the parties in the case are people who have actually been dissuaded or prevented from voting. The case might be better left to ripen until an individual can claim that he or she was disenfranchised by the law. If that happens, the logic and consequences of the Indiana law should be put under rigorous scrutiny.

But another concern with voter ID is the registration and tracking system that might be dreamt up to implement it. In 2005, the Commission on Federal Election Reform (known as the “Carter-Baker Commission”) issued a report finding “no evidence of extensive fraud in U.S. elections or of multiple voting,” though it sometimes does occur and could affect a close election. To inspire confidence in the system, the commission recommended using the national ID card created by the REAL ID Act as a voter registration card.

A national registration system for voting would quickly be repurposed and used for many other kinds of regulatory control. There is no shortage of proposals for national registration and control of citizens. Should the voter ID tempest in a teapot boil over, the tiny specter of voter fraud could thrust a mandatory national ID into the hands of law-abiding citizens.

The Constitution gives Congress power to regulate the elections that select its members and, to a lesser degree, the president. But Congress does not have to use that power to its fullest extent. States recognize their own interests in fair elections, and they should experiment among themselves with ways to secure elections while making sure the vote is available to all qualified people.

The qualifications to vote are typically residency, age, sufficient mental capacity and absence of a felony conviction. These credentials can be proven without identity cards and databases.

Clumsy voter ID rules should be avoided. A national voter ID system should be taken off the table entirely.