Originally Posted by
Loren Pechtel
Actually, there is a good reason to fingerprint non-citizens: Espionage.
When presented with a US passport they can check to see that the photo on file matches the person and that the passport is valid. It would be pretty hard to slip in on a forged/tampered US passport.
They can't make such checks on foreign passports. Fingerprints won't catch forged foreign passports *THE FIRST TIME* but it means that once a spy has come into the country once they can never come in under another identity.
DHS's fingerprint process doesn't necessarily catch people using forged foreign passports repeatedly to enter the US.
Much the same goes for DHS's fingerprint process and use of fraudulent passports or fraudulently used "legitimate" passports.
DHS's fingerprint matching is also otherwise something that can be made to fail, no less so when having the backing of resources of some of the states -- so-called "friendly" or otherwise -- that engage in espionage against the US.