In that case, I stand corrected and I am sorry about that.
However, it does sound like it would be really easy for the US government to convince everybody that citizens should also have their finger prints scanned to confirm their identity.
In fact it is really really odd that they only scan foreigners to confirm their identity.
I've even been scanned once leaving.
That means they have a database of all US and non-US citizen's who has entered the country.
I am not a US citizen, but I don't understand why Americans have never complained about it?