There's a very good reason why Americans don't carry federal identification at all times, even though other nationals often do. Constitutionally, states must h

There's a very good reason why Americans don't carry federal identification at all times, even though other nationals often do. Constitutionally, states must honor with "full faith and credit" other states' "public Acts, Records, and judicial Proceedings" (Article IV), so for the most part, a state government-issued identification card has the same authority as a federal-issued one, since each state is obligated to give it the same credence they would their own. (America's extreme form of federalism is to thank.) Although there are obviously instances where this isn't necessarily true, carrying a passport around along with a state ID would be redundant in most cases within the US -- even the TSA, for example, puts a state ID on the same level as a passport. I know this wasn't REALLY the point of this article, but it did make me wonder about the constitutional/legal issues involved.