Because some of the terrorists who carried out the September 11 attacks had lived for months in the United States even though they were known to be security risks or had visa violations, proposals have begun to gain traction for creating a national identification card. Proposals vary as to whether everyone in the country would be required to possess and carry a card, whether the system would be voluntary but available to everyone, or whether it would be required only for noncitizens and thus integrated into the visa system. It also is unclear when and where the card would be utilized. This brief explains how various national ID proposals would work and the trade-offs connected to them, weighing different plans’ likely efficacy against terrorism, potential abuse of civil liberties, and cost effectiveness.

The Century Foundation offers a list of answers to some of the most frequently asked questions concerning a national ID card program. The piece explains what a national ID card is, how it is a terrorism prevention measure, the privacy implications of such a program, and who is for and against such a program.