[anigbrowl]

They might do so someday, but it has been explained time and again why this is not a very effective strategy: it will hit a relatively small number of people, it will be in an enclosed area so media access and thus graphic coverage will be limited, and airports are uniquely well-provisioned with emergency services because of the non-negligible risk of plane crashes, which will limit the impact. So the 'return on risk' for the terrorist is relatively low - it would scare people and put them off flying for a bit, but it wouldn't be an epic disaster.

Realistically it would be hard to kill more than 25-50 people, and the media coverage would consist of footage of ambulances, sober-faced people in uniform, and crying friends and relatives. Look at the history of conflicts where bombings were common, like Northern Ireland, and you notice that crowds don't necessarily mean mass casualties. The most deadly bomb set off during the Irish troubles was at an outdoor market in a town called Omagh, and killed 29 people - but that was a car bomb. Also, in a terrestrial bombing there are also tales of heroism as people help each other, emergency services turn up to help, and so on, which dilutes the sense of horror and helplessness. You could see that with the Boston bombing last year, which was ultimately more effective in drawing people together than it was in terrorizing them.

A plane blowing or otherwise falling out of the sky is a much bigger deal, because it will almost certainly mean the death of everyone on board, plus it has the potential to cause considerable destruction on the ground. Even excluding terrorism, there was high awareness of the Air France plane that crashed in the Atlantic and of course the Malaysian Airlines plane that mysteriously vanished earlier this year. In a terrestrial bombing, you might be unlucky and die, but you might also be lucky and suffer only superficial injuries, or be able to make it to safety, or whatever. In an aerial disaster you and everyone else are basically helpless because if the initial disaster doesn't kill you the fall will. Situations involving helplessness and inevitability are a great deal more frightening to people in general, more so when multiplied by a large number of people.

[mootothemax]

For what it's worth, the BBC bombing by one of the IRA splinter groups shook my then-house's windows, and I've been evacuated before that for IRA bomb warnings.

Maybe that's shaping my views when I think that the number of deaths isn't the only goal of terrorism. Rather, it's to scare and inconvenience people and the authorities.

Let's say "only" 20 people died. I think that would result in yet more security checks. I'd love to be wrong on this, and maybe that's why an attack like this hasn't happened to date - to paraphrase you, it'd be pointless.

I guess looking at it coldly, we should just be thankful that the on-the-ground expertise dies in every attack.

[mikeash]

I don't quite buy it. The Boston bombs were extremely amateur and small, and yet they managed to shut down the entire city for a day. A big rolling suitcase full of powerful explosives and shrapnel set off in a security line at peak time in a large airport would be way worse. And if that's not enough, do it again, and again. One security line bombing a month until the end of time would be fairly easy and would cause complete chaos.

The real reason this doesn't happen is that there are almost no terrorists in the US in the first place. There is plenty of opportunity, whether it's airport security lines, sporting events, or simply using one of the sixteen thousand trivial ways to get contraband past the TSA. The only reason planes aren't constantly falling out of the sky and our airports aren't all smoking craters is that essentially nobody is truly willing to carry out such attacks in the first place.

[anigbrowl]

Your arguments are not really responsive.

A big rolling suitcase full of powerful explosives and shrapnel set off in a security line at peak time in a large airport would be way worse.

I gave you an example of a car bomb that killed only 30 people even though it was set off in a crowded market. Have you ever seen a car bomb go off? I have, it's huge. What's your basis for assuming that a suitcase bomb is going to be so much more devastating?

Certainly there is plenty of opportunity, but you're making a chicken-and-egg argument by saying there's very little terrorism, therefore security is a waste of time. I'm saying that that the payoff for the risk involved is not enough for most people.

And if that's not enough, do it again, and again. One security line bombing a month until the end of time would be fairly easy and would cause complete chaos.

I mentioned the northern Irish terrorist problem because I'm from Ireland and later lived in London. One bombing a month does not cause complete chaos, it just pisses people off and creates more public support for stiffer security measures, more intrusive surveillance and so on.

I suggest you step back from your assumptions of what would happen and look at available documentation of what actually does happen in countries with long-running insurgencies or terrorist problems, from the UK to Sri Lanka to Colombia, cases of actual disasters (whether engineered or accidental) at airports and public transit hubs.

[mikeash]

The suitcase bomb was compared to the ridiculous pressure cooker bombs used in Boston, not car bombs. I did not state that they'd be worse than a big car bomb. I did not make any such comparison.

You misunderstand my argument. I'm not saying that there's very little terrorism, therefore security is a waste of time. I'm saying that many of our security measures are a waste of time because they don't stop terrorism, and I say this because they're trivial to bypass. That terrorism is so rare in this country is not because of agencies like TSA, but because there are approximately no terrorists to be stopped in the first place.

In places where there are a lot of terrorists, they carry out bombings pretty regularly. Regardless of whether you think it's effective, they clearly do. Yet they don't do it in the US. And it's not because TSA is stopping them, nor is anybody else set up to stop those sorts of attacks that regularly happen in places like Iraq. The only reasonable conclusion is that they don't happen because nobody here wants to carry them out.