Certainly fingerprinting foreigners doesn't do much for security. Effective covert action would give the US public the impression that nothing is being done. Creating a huge fuss by inconveniencing foreign visitors, despite being totally useless at preventing terrorism, at least gives some sense that the administration is doing something useful to protect the public. A false sense of security. The US remains just as un-protected as it was before 9/11 and it is just a matter of time before the next atrocity occurs. Towards the end of the presidential election campaign would seem a likely time - an attempt to influence the result, as with the Madrid atrocities in Spain - and it will most likely be carried out by people who have been living quietly in the US for several years without arousing any suspicion.
Covert operations are the only effective way of dealing with terrorism. In Britain, as a result of 30 years of terrorism, Big Brother is watching. The movements of individual UK residents can be followed on video wherever they go. Journies are tracked by monitoring which mobile phone antennae the target's phone is linked to. Mobile phone traffic is routinely monitored by GCHQ, and purchases of fertilizer and other chemicals capable of being used to make explosives are recorded and reported. The general public are barely aware of these things around them, but don't imagine that the recent arrests of terrorist suspects were just a case of the police striking it lucky...