It is a peculiarity of the Abrahamic monotheisms that they see, at the heart of society, the idea of covenant. Covenantal politics are politics with a purpose, driven by high ideals, among them the sanctity of life, the dignity of the individual, the rule of justice and compassion, and concern for the poor, the widow, the orphan and the stranger. G.K. Chesterton called America a "nation with the soul of a church". Britain used to be like that too. In the 1950s there was no television at certain hours on Sunday so as not to deter churchgoing. Sundays helped keep families together, families helped keep communities together, and communities helped keep society together. I, a Jew growing up in a Christian nation, did not feel threatened by this. I felt supported by it — much more than I do now in an ostensibly more tolerant but actually far more abrasive, rude and aggressive society.

What is unique about covenant is its seemingly endless possibility of renewal. It happened in the Bible in the days of Joshua, Josiah and Ezra. It happened in America between 1820 and 1850 in the Second Great Awakening. It happened in Britain at the same time through the great Victorian social reformers and philanthropists. Covenant defeats the law of entropy that says that all systems lose energy over time. It creates renewable energy. It has the power to arrest, even reverse, the decline and fall of nations.

None of us should be in any doubt as to the seriousness of what is at stake. Europe today is pursuing the chimera of societies without a shared moral code, nations without a collective identity, cultures without a respect for tradition, groups without a concern for the common good, and politics without the slightest sense of history. Ibn Khaldun, were he alive, would tell them precisely where that leads.

The question is not radical Islam but, does the West believe in itself any more? Is it capable of renewing itself as it did two centuries ago? Or will it crumble as did the Soviet Union from internal decay. "We have met the enemy," said the cartoon character Pogo, "and he is us." That is the challenge of 9/11. It's about time we came together to meet it.