When writing about terrorism it is difficult to avoid biases, cliches, or moral judgments. Among the traps is to blame religions (Islam in particular) and to fantasise about a "conflict of civilisations" without realising that, for example, so-called "radical Islamists" kill more Muslims than Christians.
If anything, terrorism in the 21st century seems to be void of any ideas, be they political, religious, or other; in the late 20th century, by contrast, ideas played a role, if often questionable (in Europe, examples include the Red Army Faction in Germany, the Red Brigades in Italy, and pro-independence movements). Today's highly materialist world is challenged by a highly materialist form of terrorism – brutal, mercenary, and not by chance, nihilistic and suicidal.
Much talk about "terrorism" is unavoidably generic. Clarity may be gained by identifying three levels of involvement in it: governments, leaders, and fighters.
