A national identity card has been opposed by many civil libertarians, even though some sort of ID is needed to fly on a commercial airplane or buy goods at many kinds of stores. A national ID card, therefore, hardly seems like an intrusion and it could do some good. If you are stopped by a policeman, he'll ask for ID anyhow, so why not have a standard ID card?
On the other hand, real privacy is being violated routinely. The government apparently thinks nothing of it. Declan McCullagh, a libertarian who has followed technology issues for about two decades, reports on a little-noticed provision in the proposed House health care "reform" that will open people's IRS data to medical evaluators.
The next step is for the IRS to be provided data from your medical records. You can see where that heads: some people will avoid doctors to avoid the IRS.
I don't recall hearing from the ACLU about this, do you?