Although, in many respects, America in its citizen surveillance has never had so much ability to be so intrusive into so many lives, yet, there are still a few things that America policing agencies do not have access to, such as a national ID card and database. If there was a requirement to have a national ID card, this would obviously necessitate having to produce such a card, upon being requested to do by policing authorities, as well as other agencies, public or even private as a form of identification check.
While it is true, that a driver's license serves as a quasi-identification card, not everybody has a driver's license, nor is it a requirement to have a driver's license upon one's body, while not driving. So too, each individual is required to have a Social Security number, but this number is NOT for national identification purposes and citizens are NOT required to provide their Social Security number to police or other legal authorities, though, the Social Security number in conjunction with an individuals' driver's license behaves as the quasi-national ID.
This would seem to indicate that Americans have some free air to breath, knowing that they actually have the right, at least on paper, to be about their business without having to actually produce papers that prove who they are. The practicality of the matter though, is that those that are not able to satisfactorily identify themselves to policing authorities will often find that, their freedom of movement, is seriously restricted or under assault, which quite obviously demonstrates that national ID law or not, the freedom to not be disturbed, unless under exigent circumstances, seems to have vanished.
While there are plenty of people that actually support a national ID card, they are fundamentally trading convenience or a false security for something that in the hands of those that wish to do harm, is a very effective discriminating tool to do so; because easy identification of those that have been classified as unacceptable, for whatever reason(s) makes it very straightforward in being able to separate the franchised from the disenfranchised.
When government authorities know exactly who you are, and exactly where you are at, the rounding up of people that are an inconvenience to state authorities, is not only easily accomplished, but it could be argued, is going to be something that will be accomplished, in way or another, sooner or later. The government wants to know everything about you, not so as to aid you, though they may speak of aid, and may even offer some kind of aid, but the prevailing reason is to control you, to manipulate you, and to eliminate all those that are not in lockstep with the prevailing governmental desires and decrees.
The national ID card is a very effective way to get everyone to get with the government and its policies, and to more readily discriminate against all those that are not with the government and its policies, basically, stifling civil dissent. A government that serves the people, does not need a national ID card, but a government that desires to be served by the people, does.