I agree with you completely that it's entirely unproven whether or not the TSA has been effective for catching terrorists. I also agree that it's a wasteful system that should be seriously reformed into something that is actually effective.
It's precisely because it's unproven that we cannot say that the TSA has never caught a terrorist. That's all I was saying. The TSA may or may not have caught a potential terrorist at some point, it's pretty much impossible to say. You can't have it both ways. Either the TSA's effectiveness is unknown (meaning they may or may not have caught terrorists), or it's known to be 100% useless (meaning 0 terrorists were caught).
In regards to occurrences of terrorists prior to 9/11, you're correct that there weren't many (any?) incidences of using a plane for a terrorist attack, but hijackings were certainly not uncommon prior to 9/11. In fact, come to think of it, incidences of hijackings are almost certainly down since 9/11. I don't think this can be entirely attributed to increased security, but I wouldn't be surprised to see it as a contributing factor.
> we cannot say that the TSA has never caught a terrorist.
But why? I am sure any such catch would have been paraded in front of media for months. Are you saying they caught a terrorist with a bomb red-handed but hid it and instead shipped the guy secretly to a prison in another country? If not, that then I think we can say most definitely that they have not caught a single terrorist. Would you agree?
> but hijackings were certainly not uncommon prior to 9/11
Obviously hijackings were not that bad. That is the reason the first two planes ended up being used as projectiles, because people thought it was a regular hijacking. Within hours everyone in the country including passengers of the plane that went down in PA learned to not think about hijackings anymore in the same way. So the problems basically "fixed" itself immediately.
You are right the # of hijackings is now lower. TSA presence might have a part to play, that's plausible. But because of the previous paragraph it also becomes irrelevant. So the reasons for having the TSA evaporate away again.
It's precisely because it's unproven that we cannot say that the TSA has never caught a terrorist. That's all I was saying. The TSA may or may not have caught a potential terrorist at some point, it's pretty much impossible to say. You can't have it both ways. Either the TSA's effectiveness is unknown (meaning they may or may not have caught terrorists), or it's known to be 100% useless (meaning 0 terrorists were caught).
In regards to occurrences of terrorists prior to 9/11, you're correct that there weren't many (any?) incidences of using a plane for a terrorist attack, but hijackings were certainly not uncommon prior to 9/11. In fact, come to think of it, incidences of hijackings are almost certainly down since 9/11. I don't think this can be entirely attributed to increased security, but I wouldn't be surprised to see it as a contributing factor.