Obviously this is the sort of thread that does act as a candle flame to trolls, so please try to drown them out with reasoned discussion.
Anyway: one thing that struck me back in 2001 was how a lot of people (and not just the US government or media for that matter) acted as though this was something new and frightening, apparently forgetting that Islamic extremists hijacking aeroplanes, and Islamic extremists attacking the World Trade Centre, were both nothing new. Granted, putting the two things together and pulling it off in a spectacular and bloody attack was new. My point here is to ask whether a 9/11-level attack - heck, you could even say a carbon copy of 9/11 itself, given that all the ingredients were already there - would have had the same kind of novel effect if it had come during the Cold War, rather than bringing the "end of history" jubilation of the 90s crashing down in flames.
A decent date for this is 1981. There are some obvious comparisons: a very right-wing president is settling into his first term, other countries are a bit worried about him, etc. We will say this attack happens in September 1981 for the sake of parallels, so Reagan has recovered from the assassination attempt on him earlier that year.
Presumably the motivation of our hypothetical Islamist terrorists would be US support for Israel - the other major motivation of Al-Qaeda in OTL (US troops in Saudi Arabia) does not exist, but you could perhaps substitute something like the US tacitly supporting secular and anti-Islamist Arab states prone to oppressing their people (i.e., Saddam Hussein's Iraq, currently fighting the Iran-Iraq War against the incipient Islamic Republic of Iran). Perhaps the terrorist group here would be drawn from Iran: we can imagine a group (freewheeling, not under the Islamic Republic's authority) deciding that giving America a bloody nose would blackmail the USA into not supporting Saddam anymore, and this of course backfires spectacularly.
My questions here are twofold. Firstly, what would the USA's response be at a time when you can't go around randomly bombing and invading countries when there's another superpower on the bloc(k), and secondly, what would the cultural effect be. While there would still be serious shock and widespread sympathy for the USA, I tend to think this would not be viewed as a "war" as it sometimes mistakenly has in OTL. Also, in OTL Putin's Russia, despite generally chilly relations with the West, tended to pay lip service to sympathising with America and the "war on terror", not least because it gave it the excuse to deal with its own vaguely Muslim-related issues (i.e., Chechnya) without the US criticising it. Ditto China with the Uighurs. Now what would Brezhnev do in the same siuation? And Deng Xiaopeng? I imagine 1981 China might be a bit more reserved and isolationist, whereas the USSR is more of an enigma: they are currently engaged in their Afghan invasion, which might alter matters somewhat.
Your thoughts?