We would be better off, and have less expense, issuing trackable cards to non-citizens -- they are so far still outnumbered by the citizens, I think. Microtransponders could give off a trace pulse at airports, bus stations and travel junctions so that we could find out when an immigrant who was not a citizen had flown off somewhere else, rented a car, etc.

Dunno how much us eit would be in prevention but it would accelerate investigations -- and it would be the US Government provising security to its citizens, rather than harassing them. If you became a citizen you could turn in your Natl ID card.

A,