National identity card
An identity card is used to prove one’s identity generally in the issuing country. It can be used as a travel document if agreed between countries, as is the case among European nations.
Several countries still issue ID cards that do not comply with the ICAO’s Document 9303 standard, but the trend is towards delivering ID cards in a credit-card like format that respects the standard.
In Europe, ID cards exist in all E.U. nations, except Denmark and the United Kingdom. Among those that have implemented it, only Austria, France, Italy and Lithuania don’t require its possession. In Portugal, a single card serves as an ID card, social security card, taxpayer card and polling card.
An optional ID card exists within the U.S.: the U.S. passport card, which is not widely used. As a driver’s license is overwhelmingly used as proof of identity in North America, some States have opted to issue ID cards for non-drivers that have the same characteristics as a driver’s license.
Securing this document is a common concern for all countries. Arguments put forward to explain its reinforcement revolve mostly around security concerns: population movements, terrorism, etc.