In Michael, Joseph Goebbels's Bildungsroman published in 1929 and based on his post- First World War diaries, the sometime Catholic wrote: "It is almost immaterial what we believe in so long as we believe in something." The dictum combines grasping opportunism and indiscriminate credulity, but is hideously revealing of a mentality by no means exclusive to Goebbels In Michael Burleigh's Sacred Causes, a sprawling trawl through the squalor of totalitarian creeds and voluntary religiosity, it is dismally commonplace.
Time and again, those with the promiscuous capacity for belief are shown to be those with the equal capacity to promote and sanction inhumane crimes. We repeatedly witness the migration of believers - "spiritual persons" - from one cult to the next. Believing in something all too evidently means believing in anything. One of Goebbels's aptitudes as a manipulator was to sate this appetite for belief by forever creating new idols, new hate figures, new "initiatives". He understood that the attention span of the credulous is finite, that any cult or political faction or communion will lose adherents unless it espouses what appears to be a constant revolution. The otherwise well-positioned German Social Democrats of 1945-47 did not understand this. They wished merely to turn back the clock to before 1933, to Marxist orthodoxy and coarse anti-clericalism.
The Christian Democrats, on the other hand, were protean and cunning. Despite the broad rupture between the Protestant denominations and Rome, there was a greater divide between Germany west of the Elbe and that to the east, which had remained pagan until the 14th century (totem poles are still common in the Baltic states). A broadly Christian government was more acceptable to both a guilt-ridden German people and to the western allies than one which shared a dogma with the Soviet Union.
Burleigh traces a coherent if twisted thread that leads from Lenin to today's noisy, intellectually stunted Islamicists. The thread is one of liberally tolerated intolerance, of western materialism's apologetic self-hatred, of the Christian churches' mutability, of every doctrine's willingness to abandon its defining catechism in the fight to preserve itself and of the universal political preoccupation with religion - whether imitative or antagonistic. Hence the hooked cross, the biblical quote, the evangelical grin and Ronald Reagan, who "appointed Him an honorary member of his cabinet". Hence, too, the murder of clergy, the suppression of texts, fatwas, persecutions and pogroms. Hitler was more or less right when he said "the Enlightenment is dead" - it certainly is so far as the political classes are concerned. Were it alive, religious faith would be treated with the amused contempt that is visited on flat-earthers and ufologists, and factional schools teaching their particular exclusivities and hatreds would not be sanctioned by government.
Yet it was tolerant, blaspheming, relativist Enlightenment figures such as John Wilkes who hoped that mosques and synagogues might become established in England, as much to threaten Anglicanism's primacy as to promote Islam and Judaism. The first mosque in Paris was built by the state in the 1920s in response to secularist petitioning for a memorial to the Zouaves and Spahis, First World War cannon fodder of Maghrebi origin. In the next war a number of Muslims would don the black of the SS. Catholics fought in Spain for both nationalists and republicans; the Basque country, birthplace of St Ignatius Loyola and strenuously devout, was infamously used as target practice by the Luftwaffe. Ad hoc alliances and compacts of convenience also exist across time. With their cosy alienation and self-pitying martyrology, today's Islamists resemble fascist thugs. And the notion propagated by unarmed Muslims that they are treated like Jews in Nazi Germany would be laughable were it not historically warped.
Carlo Ginzburg long ago drew attention to the kindred myth systems exploited by the early Nazis and the ayatollahs. Burleigh does not concur. He contends that much Islamist dogma from Sayyid Qutb onwards belongs rather to the late 19th-century European tradition of anti-urbanism that calumnises cities as licentious and decadent, calls for moral renewal, equates pastoralism with goodness and is covertly anti-Semitic.
But the difference between Islamists and their supposed precursors is that William Morris, and others like him, did not have much of a career as a suicide bomber. Printing expensive wallpaper is not traitorous; blowing up your fellow citizens is - even if you refuse to acknowledge that fellowship, in the manner of Gerry Adams's father, who lit fires to guide German bombers to Belfast targets. In an aside, Burleigh tells us that Adams's party, Sinn Fein, holds an annual celebration in honour of the IRA chief of staff and German spy Séan Russell. It is this sort of information that makes Sacred Causes so valuable: the tiny details that might be written off as mere human interest, but that over and again reveal a sub-human sump of murderous impiety.