How Islamic terrorists reduced terrorism in the US

Much of the reduction might be for non-obvious reasons, like whatever happened around 1980.

Exactly. Much of the reduction is for the same reasons you no longer hear much about cults, or about hijacking planes to Cuba (or about anarchists car-bombing Wall Street or trying to shoot the Queen, for that matter), or about communism. There seems to be something about the shift from a traditional partially-industrialized society to a post-industrial one which triggers this sort of great social upheaval, which manifests in part as new religious movements (labeled cults) and violent action (terrorism or guerrilla), which eventually get discredited and cease to be alternatives. In Japan, you had the 'rush hour of the gods' with many syncretic Buddhist groups and the Red Army (to name the most infamous one) with a last gasp in Aum Shinrikyo; in America, you had those but also Weathermen etc; in South Korea with its later development the process is still ongoing, with the cults take on a Protestant Christian form - the recently deceased cult leader associated with the Sewol Ferry disaster an interesting example - and the violence tends to be associated with North Korea (various assassinations or attempts come to mind).

I know you didn't make the graphs, but ...

I don't like line graphs. They're a kind of smoothing, but almost never the right choice. The first two graphs are smooth enough that it hardly matters what you do, but I redid the third as a scatterplot plus a loess curve.

Here's the loess superimposed on the line graph, if you want to compare them. I got the data here, linked from here

A find your hypothesis interesting but let's discuss a few different possible causal mechanisms than your primary suggestion (and it is possible that this drop is some combination of causes):

1) You bring up the possibility that the threat of Islamic terrorism has lead to a substantial increase in security levels, so more terrorist incidents are stopped or never get off the ground. If this is the primary cause then I'd expect most of the drop off to occur after the first bombing of the WTC in the 1990s, and a heavy post-9/11 drop-off but your graph shows a drop-off staring before then but then shows the most clear cut drop-off in the mid 1990s, so this may be part of the effect. The fact that the drop-off rate doesn't get massively faster after 9/11 possibly undermines this. I think your point is also a valid one which suggests this isn't what is happening or at least is only a small factor of what is going.

2) The American political scene may in some ways simply be more civilized than it was in the 1960s and 1970s. True in many ways things at the congressional level feel more partisan, but it may be that the groups which felt like they had no options other than violence don't feel that way as much because they have politicians who represent their interests. Both the far-right and the far-left have more elected politicians than they did in the 1960s, as do many racial minorities. In that context, it looks like one has avenues that are not violence for getting voices heard.

3) Part of the decrease may be due to the same effects (whatever they are, such as higher abortion rates, lower lead levels, better education) that have reduced violence levels in general. As violent crime has gone down, so has the type of violent crime we generally put in a separate category.

4) (Related to point 2) The internet gives people a feeling like they can get their voices heard with a feeling of (possibly illusionary) productivity, whether it is organizing boycotts or letter writing campaigns or simply venting to like-minded people.

Responding separately to your point about lone-wolf cases, part of the issue here may be classification. Many lone-wolves have ideologies or the like which they claim are motivating them, even if they have their own unique spin. It may be that we're choosing to classify them as such rather than seeing them as part of their claimed ideologies. Also, it may be that lone-wolves are easier to be in the US since guns are more available whereas in many countries (especially in Europe and Japan) the lack of easily available firearms means that people need to cooperate in larger groups to get weapons.

We see a dramatic drop in terrorist acts in the US after 2000.

Do we? I see a sawtooth-decline starting in 1995/6, with 2000/1 not deviating from the trend.

Your analysis is surprisingly Americo-centric. The 1970s saw very serious terrorism (far worse than America) in the UK, Germany and Italy, all of which are now very peaceful countries. Did 9/11 also make terrorism un-Italian?

Secondly, your timing is all wrong. The fall in terrorism worldwide long predates the rise of specifically Islamic terrorism.

Thirdly, Islamic terrorism is the intellectual and organisational descendant of secular Arab terrorism and is received in much the same way. The only innovation is the suicide bomber. Yet in the period that you claim terrorism was 'cool,' there was no shortage of horrific atrocities committed by) Arab terrorists - often in co-ordination with Western groups, such as the RAF. Do you think those were seen as 'cool'? Abu Nidal was the bin Laden of his day, and got much the same popular portrayal. In fact, the keffiyeh-clad Arab terrorist as staple villain in action movies hasn't changed one jot in forty years, just that then he would be a member of PFLP or Fatah, and now al Qaeda.

half of all attributed [terrorist acts] in the US from 2000-2013 are tagged "Individual".

The NSA/FBI might be doing a great job of stopping coordinated terrorist attacks and infiltrating and deterring groups that might launch attacks on America. Plus, I get the sense that a significantly higher percentage of U.S. than European Muslims are willing to cooperate with the police to stop terrorism.

You're graphs are too low resolution to read.

As for individual actors in other nations, what about Anders Behring Breivik? You might find this list helpful:

https://en.wikipedia.org/wiki/Lone_wolf_%28terrorism%29

I checked 200 cases from other countries and did not find one case tagged "Individual".

Breivik..?

The lone gunman thing, where someone flips out and shoots up a Navy base, or bombs a government building because of a conspiracy theory, is distinctively American.

A conspiratorial explanation: perhaps the data has been manipulated to downplay terrorist coordination in America. There would be a couple reasons to do that, depending on the audience. For ordinary citizens, a collection of nutcases might be less scary than a dark underworld of coordinated cells. For terrorists and wannabe terrorists, a collection of uncool loners might less glamorous (as you've suggested too) than a Team of Subversive Evildoers.

But this doesn't explain why the same manipulation hasn't been done for other countries.

If you stratified the data on terrorist ideology by sect, would Wahhabism by the underlying confounder, rather than Islam?

Islam explicitly advocates for violent Jihad. Countries like Australia should deal with terrorism as a policing and arts/culture issue, than a military problem. In fact, having no military might be in our best interest. There are a number of nations in the world with no militaries, some in particular unstable and criminal parts of the world, like Costa Rica, which don't have any military issues, as far as I know. In fact, it would seem that the best defence is no defence, assuming the stable implementation of military law, which is probably predicated on policing nations like the USA intervening elsewhere. Logic summarised here. I don't expect much from politicians anyway. Everyone from healthcare administrators don't act in evidence based ways to the military don't respect the truth, it seems that it takes the somewhat autistic utilitarianism of Lesswrongers for that kind of pedantism.

We really should consider the possibility of having to stomp on Islam as an existential risk, or at least stopping immigration from Muslims' weak and dysfunctional countries until Muslims can show good citizen behavior, if ever. .

If you engage in Long Game thinking, you should also have to consider the need for prophylaxis against the emergence of new nuisance religions in the coming centuries. I think randomness has fooled us into thinking that undesirable things from the Before-Times will never come back because we have "progressed beyond that,", when I wouldn't assume anything of the sort.

http://tvtropes.org/pmwiki/pmwiki.php/Main/LongGame