A New Mexico legislator has just proposed that his state’s election officials study the feasibility of a biometric voter identification system. Rather than require voters to show a document that not everyone possesses, the law could require election officials to collect a piece of information – a finger image or an eye scan – from all voters, which would confirm their identity at the polls.

Republicans would have the ID laws they claim are needed to protect against voter fraud. And Democrats would have a system that doesn’t disproportionately hurt minorities and the poor. Both parties could declare victory in the war over voter ID and move on.

It would be a costly way to prevent an all-but-nonexistent crime: voter impersonation. If that were the only rationale, it would be hard to justify the cost. But other benefits are possible. In states that bar felons from voting, for example, biometric images could be cross-checked with prison records to identify anyone who is illegally registered.

Training poll workers to use the technology would be a challenge. But it would not be insurmountable, as other countries are showing. From Brazil to Yemen to the Philippines, biometric voting is spreading.

In the United States, new voters could submit their fingerprints as part of the registration process, and all other voters could do so at the polls. This would allow a state to gradually phase out its ID requirements. Safeguards would be needed to keep biometrics from being encrypted with other personal data and to ensure that any technical problems do not disenfranchise voters.

A functioning democracy rests not only on access to the ballot box but also on public confidence in the integrity of elections. And there is overwhelming public support in the U.S. for voter ID laws. Those who wish to avoid them need to start offering a better option. A legislator in New Mexico may have just put his finger on it.