I look and listen to Anders Breivik as he is televised standing trial in Oslo, Norway for the murder of 77 people and I think of Nathuram Godse. Breivik admits to murder and so did Godse. They both killed people to kill an idea and declare war on an inevitability.

Godse was judged sane and hanged not as a murderer but as an assassin, a category which recognises, even marginally, an ideological motive. Breivik and his lawyers have a single aim. He killed 69 young members of the Norwegian Labour Party at a youth camp to gain, he says, a platform to tell the world why he did it. He sees himself as part prophet and part sacrificial lamb in a cause. He told the court that just as the families of the people he murdered have 'lost everything', so has he. If the court judges him insane - and any common sense assessment should proclaim him such - the platform is undermined. His ideology is equated to raving.

Is common sense, or even the judgment of psychiatrists, who could certify him on the evidence of palpable megalomania, paranoia and delusional behaviour, necessarily right? Breivik has a view of the world which can be compared to that of jihadist Islamites who fly planes into buildings or indeed to that of Nathuram Godse. All of them deserve the title of 'fanatic', but where does fanaticism end and insanity begin?

Breivik, through the liberal mechanisms of European law, has broadcast his conviction that the immigration of Muslims to Europe is eroding European civilisation and is a conspiracy to have it implode. He perpetrated the ideas in a 15, 000-page rant posted on the internet - his own Mein Kampf. He refers to Islamisation as medieval barbarism, the irony of which is that he too is peddling a medieval philosophy with different blood lusts. He calls his organisation, which has been challenged as being a fantasy, The Knights Templar, invoking the Crusades coupled with Norse legend fantasies of racial purity - call it the Walkyrie syndrome.

Till Karl Marx came along, most theories of history were obscurantist. From Herodotus on it was assumed that wars were caused by the greed and belligerence of kings and would-be conquerors, that loot, slavery, slaughter and genocide were the prizes or even the side-effects (what Americans call collateral damage!) of ambitious enmities. Since Marx's thesis, a current of historical thinking looks for the material benefits of conflicts originally seen as ideological in origin. So, for instance, a Marxist may say that the Crusades were not primarily about establishing Christian or Muslim rule over the Holy Land but about the control of trade routes to the East.

In our era of globalisation, multinational companies go where they can make most profit - either because the infrastructure suits their processes or because labour is cheap. The complementary move is that of labour which moves to where a larger wage, or any wage at all, is available. It ought to be evident, even to Anders Breivik that the millions of South Asians who go to the Gulf to work for petrodollars are not there to convert Saudi Arabia or Dubai to Islam. Breivik and the Islamicists, whom he sees as the ultimate enemy, share the belief in destructive conspiracies. He believes that the Labour Party of Norway and the other liberal non-fascist political formations of Europe are in a conspiracy to import jihadists to further a policy of multiculturalism and so destroy Western civilisation. He killed eight people with a car bomb in Oslo outside the Labour Party's headquarters and then proceeded to murder 69 young people attending a Labour Party youth camp because he says he saw them as the 'brainwashed' troops of the enemy. In what must be one of the most shameless and unselfconscious reversals of truth he said he was therefore "acting in self-defence".

The Islamicists of the al-Qaeda or e-Qaeda breeds believe that the conspiracy has been hatched not by political parties, who are mere puppets, but by the Devil himself. Western civilisation, its sexual mores, its politics, art, religion and democracy are all works of The Great Satan who is in control of a world that is even now pushing wedges into the Muslim Umma itself. Their terror and random killing of office workers in the Twin Towers, passengers on Madrid or London trains and even congregations of Muslims whom they condemn as infidels, are akin to Breivik's contention that the 'brainwashed' are fair game.

For these fanatics, the world is divided in two, an idea first forced upon civilisation by the 3rd-century Zoroastrian heretic Mani who preached that good and evil were battling it out and that the troops of the pure must be recruited to fight 'The Lie'. No good telling them that since the age of reason, the world is actually divided into three: the imperfectly rational, the wilfully irrational and the insane. The UK police and security services have foiled and brought to court at least 25 cases of Islamist terror and conspiracy in the years since 9/11. These maniacs exist and the propaganda machines of their supreme delusion are actively recruiting more adherents who have to be hunted down and brought to justice, not for their beliefs but for their conspiracies to kill and maim.

One may also recognise that the very liberality of the West which Breivik claims conspires to destroy Western civilisation is struggling to come to terms with how to deal with the existence of this canker. Detention without trial;the inability of governments (rightly) inhibited by human rights laws from deporting terrorists to countries with no respect for these;the blurred distinction between free speech and criminal instigation are all symptoms of this uncertainty. Breivik proclaims he has risen above the uncertainty, that murdering young socialists should be the contemporary Crusader's strategy. Allow me then to stray for a moment into his notional medieval universe and hope his soul rots in hell.