However misguided Western governments may have been, they understood then that they were dealing with normal historical conflicts. Today the Prime Minister describes Iraq as "the crucible of global terrorism", when it is clear that the conflict in that country is partly a nationalist insurgency against American occupation and partly an emerging civil war. The sobriety and realism of the past have been lost, and our leaders seem incapable of thinking about the dangers we face - some of them serious enough - in other than apocalyptic terms.
We would benefit from more clarity in our thinking about terror and terrorism, and this seems to be what Terry Eagleton aims to provide in Holy Terror. The book is billed as the first to discuss the idea of terror in its cultural, philosophical and metaphysical context. While this may not be strictly accurate, it is true that very few of the thousands of books on the subject have explored it in a larger context of ideas.
A study of this kind is sorely needed, but there are several problems with Eagleton's effort. One is that the idea of terror is even more amorphous than that of terrorism. The only way of giving it clear definition is to focus on specific questions and try to answer them, and unless this is done the risk is of rambling - a danger exemplified in Holy Terror.
In the course of an indefatigable tour d'horizon, Eagleton cites practically everybody who is anybody in Western thought (other intellectual traditions are not discussed) but it is often unclear what these authors are meant to be talking about. Henry James and Aquinas, Aeschylus and James Joyce, Freud and Shakespeare - to mention only a few of the figures that flit past - are names to conjure with, but it is only by relying on a hugely extended metaphor that they can be said to have terror as a common theme. Reading these authors in this way is anachronistic, and does not enlighten us as to the sources of anxieties. At its worst the result is not much more than an exercise in academic punning.
Eagleton does advance a highly specific - and to my mind highly plausible - thesis about the origins of terror as a modern political phenomenon, but he fails to follow it through. At the start of the book he writes that terrorism "first emerged with the French Revolution - which is to say, in effect, that terrorism and the modern democratic state were twinned at birth". Here Eagleton is on to something. Mass murder is a universal human evil but we owe the idea that it can be a means of liberating humanity to the Jacobins, who pioneered terrorism in the modern sense.
There are plenty of examples of systematic terror and extermination in earlier times. Think of Pope Innocent III's crusade against the Cathars of southern France at the start of the 13th century, which cost the lives of around half a million people over a period of 40 years. Killing people to save their souls is a thoroughly mad idea, but the Jacobin notion that systematic terror can be the path to universal freedom is even madder, and it lies behind some of the worst crimes of the 20th century.
Eagleton is well aware of the connection between political terror and the modern pursuit of freedom, and it is explored in some illuminating passages in Holy Terror. However, he has a blind spot when it comes to terror perpetrated in the service of socialist ideals. He tells us that "socialists have always rejected the tactics of terror" - as if Lenin was a fringe figure in the history of socialism and in no way involved in constructing the Soviet apparatus of state terror. It may be Eagleton subscribes to the academic cliché that the former Soviet Union had nothing to do with socialism and was simply another version of Russian despotism, but this runs up against the awkward fact that state terror has been a feature of all communist regimes. Soviet Mongolia, the German Democratic Republic and Stalinist Poland had very different cultures, but during the communist era all suffered show trials, mass imprisonment and a ubiquitous secret police.
Terror cost many more lives in Russia and China than elsewhere, but one reason for this is that, for a time, the communist programme was carried further in them than in other countries. The millions of people who died there did so not because the communist project was compromised or deformed but because it was consistently pursued.
Eagleton's reluctance to acknowledge the fact that some of the 20th century's worst examples of state terror came from attempts to realise a humanist political project is understandable, but it is also a pity. One of the merits of Holy Terror is that he is ready to explore the religious dimension of modern politics: the netherworld of eschatology and myth that lies beneath secular political belief.
Eagleton is not afraid to use the language of sin and redemption, and if there is a consistent thread of argument in this book it is that, whatever their political and economic causes, modern revolutions also express religious needs - however deeply repressed.
The humanist projects of universal emancipation that sprang from the French Revolution were secular versions of a Christian conception of salvation; political religions, in which the promise of transcendence was replaced by the hope of a transformed life on earth.
One of the reasons the liberal West finds radical Islam so disturbing is that it forces secular cultures to confront the fact that religion is pervasive and inescapable, and nowhere more so than in the paradigmatically modern pursuit of freedom. This is a truth of some importance, and it would have been useful if Eagleton had pursued its implications more thoroughly.
John Gray, professor of European thought at the LSE, is the author of 'Al Qaeda and What It Means to Be Modern' (Faber)Reuse content