When the end of ideology was celebrated -- first in the 1950s and then, more emphatically still, in the 1990s -- no one foresaw that religion, the bane of politics in the first half of the 20th century, would return to that role with a vengeance.
Daniel Bell and Raymond Aron wrote about the end of fascist and communist ideology in the hope that we would enter an age of pragmatism in which politics would be a subject of argument and debate, not belief and total worldviews.
Karl Popper's approach to politics, one of reason and critical discourse, had come to prevail. And when -- after the collapse of communism in the Soviet Union -- the end of history seemed near, ideological politics was thought to have vanished forever.
But history does not end, and it is forever full of surprises. Francis Fukuyama's End of History and Samuel Huntington's Clash of Civilizations appeared within a mere three years of each other in the 1990s.
A decade later the return of religion to politics is visible for all to see -- and for many to suffer.
Those books are not just academic discourse, but mirror real developments.
By the time the false religions of totalitarian ideologies were defeated, it seemed that real religions had long passed from the political scene. In some countries, formal allegiance to religious faith was symbolized by gestures and rites.
Yet no one thought much about it when US presidents of different faiths swore their oath of office to God and country.
In Westminster, every parliamentary sitting begins with Christian prayers presided over by Speakers who could be Christians or Jews or non-believers.
Not all democracies were as strict as France in their formal secularism, but all were secular. Law was made by the sovereign people and not by some superhuman being or agency.
Suddenly, however, this secular commitment is no longer so clear. Religious fundamentalists claim that the law must be anchored in the belief in a supreme being, or even based on revelation. Christian fundamentalism in the US has come to dominate large segments of the Republican Party.
In Europe, the Vatican lobbied for acknowledgement of God in the preamble to the proposed European Constitutional Treaty.
Israel has long avoided drafting a constitution, because its secular citizens fear that orthodox Jews would impose their values on them.
Likewise, the Shariah, Islamic law, entered political life in its least enlightened version in hopeful democracies like Nigeria, to say nothing of Iran.
Islamic fundamentalism -- Islamism -- has spread to all countries in which there are significant numbers of Muslims.
Why has religion returned to secular and democratic politics?
The main reason is probably that the enlightened countries of the world have become unsure of their values, even of the Enlightenment itself.
A moral relativism has spread, leading many to accept the taboos of all religious groups in the name of tolerance and multiculturalism.
Cartoons of Mohammed are not published, and Mozart's opera Idomeneo is not performed, in order to avoid offending religious sensitivities. And in the end, when the publication and the performance take place, they become a demonstration almost intended to offend.
One can understand that enlightened Muslims (of whom there are many) find it upsetting that the world in which they want to live is in fact frail and vulnerable.