It is all too much. Look around at the poverty, the tyrannies, the broken states, the ethnic conflicts, the global marketplace in weapons of mass destruction. Reflect on the wickedness of those whose corruption of Islam brings death and mayhem to our cities. We cannot fix everything. Better to man the barricades.

The existential threat of a nuclear holocaust has been replaced by that of the pervasive insecurity of global terrorism. The dangerous order of the cold war has been replaced by the unpredictable chaos wrought by the suicide bomber. In the clash of ideas with liberal democracy, communism has given way to extreme Islamism.