In the United States most citizens are identified by either their driver's license, birth certificate, social security card, or passport. In most instances, the driver's license serves as adequate identification. However, something called a national ID card is currently in the works for America, and is already on the brink of being introduced in other nations. The Real ID Act has been in the works with Congress for many years now, and proposed a National ID Card for all US citizens. The card would have a barcode label that could be scanned by airport security personnel, cab drivers, shops, and any other place where people eat, live, and spend their money.
Right now, national ID cards are in use in much of the world, including most of Europe, Thailand, and Singapore. Both the United States and the United Kingdom have debated the pros and cons of adopting a national ID policy, but approval is on the horizon.
While a national ID card might sound appealing to some, there are groups who are well aware of the many dangers it poses. For one, privacy rights and personal information would be obsolete. People's home address, eye color, weight, and many other identifying factors would become a matter of public record, no matter what state the person was in or what the circumstance. A simple symbol scanner would be able to access this critical information in an instant. This has prompted quite a controversy for those who oppose it, saying that it violates Constitutional rights. It is something that several human rights groups are trying to fight.
Here is some more information about the national ID card: