Originally Posted by Bart
In all reality, I don't think you'll ever see TSA or similar screening at bus stations, train depots and subways. Congress and the American people wouldn't stand for the expense involved. Chertoff has already said that these transportation venues are pretty much on their own, and he won't commit DHS (read TSA) to providing security.
I think the reason for the focus on aviation as opposed to any other means of transportation is because the idea of flying bombs has a much more devastating impact than a blown up bus, train or subway. Hate to reduce this down to a matter of acceptable and unacceptable casualties, but that's essentially what it all boils down to.
After secured cockpit doors, flight crews that stay in the cockpit and do not surrender control of the plane, and passengers who will resist, 9/11 style attacks will almost certainly not occur again. Flying bombs, on the other hand, are a real possibility because Congress has not addressed the lack of screening of cargo on passenger airliners and DHS/TSA has not raised this gargantuan loophole in aviation "security". Detonate an explosive in a cargo hold of an airliner over a large city, and casualties on the ground could be enormous, probably reaching unacceptable levels. But it is more impressive to search passengers, so let's just play ostrich and hope that no explosives are ever detonated on a passenger airliner. Forget Lockerbie, Air India over Canada, accidental disaster that was Valujet over the Everglades, ...