Another reason "Islamism" is a useful concept

Islam has a history that makes it more than what its true believers often argue; both Muslims and anti-Islam polemicists often think the question of what is Islam is exhausted by the foundational texts and so, given the relentless pitting of believers against (frequently cursed) unbelievers in these texts, it is pointless to distinguish, say, radical "Islamism" from Islam. Yet Islam remains a work in progress, as great propagandists have always known, and we need ways to denote what is particular to our times:
Nazi Propaganda for the Arab World :: Reviewed by Daniel Pipes

Ideas the Nazis spread in the Middle East have had an enduring twofold legacy. First, as in Europe, they built on existing prejudices against Jews to transform that prejudice into something far more paranoid, aggressive, and murderous. One U.S. intelligence report from 1944 estimated that anti-Jewish materials constituted fully half of German propaganda directed to the Middle East. The Nazis saw virtually all developments in the region through the Jewish prism and exported this obsession.

The fruits of this effort are seen not only in decades of furious Muslim anti-Zionism, personified by Arafat and Ahmadinejad, but also in the persecution of ancient Jewish communities in countries like Egypt and Iraq, which have now shriveled to near-extinction, plus the employment of Nazis such as Johann van Leers and Aloïs Brunner in important government positions. Thus did the Nazi legacy oppress Jewry in the Middle East post-1945.

Second, Islamism took on a Nazi quality. As someone who has criticized the term Islamofascism on the grounds that it gratuitously conflates two distinct phenomena, I have to report that Herf's evidence now leads me to acknowledge deep fascist influences on Islamism. This includes the Islamist hatred of democracy and liberalism and its contempt for multiple political parties, preference for unity over division, cult of youth and militarism, authoritarian moralism, cultural repression, and illiberal economics.

Beyond specifics, that influence extends to what Herf calls an "ability to introduce a radical message in ways that resonated with, yet deepened and radicalized, already existing sentiments." Although a scholar of Europe by training, Herf's detective work in the U.S. archives has opened a new vista on the Arab-Israeli conflict and Islamism, as well as made a landmark contribution more broadly to an understanding of the modern Middle East.