The problem of the global revival of Islam in the 20th century (catapulting and catalyzing into the 21st after the jump-start of 911) was -- ineptly and unintentionally -- enabled by various general Western policies and variations on a mindset indulged by Western governments and their civilian apparatus. What should have been implemented by the West -- even as far back as the 19th century, but certainly in the 20th -- was a Realislamik, a geopolitical policy resembling "Realpolitik" but calculated to strategize based on a literacy of Islamic jihad. Such a literacy would be based on, for example, the sound insights Greenfield articulates in a recent essay about Islam, and a literacy that avoids the naive notion (indulged by Greenfield's own bosses at FrontPageMag; scroll down if you go there to read my various comments) that any Muslims exist who do not enable Islam so analyzed.
One major sign & symptom of this mindset was the assumption, throughout the 19th and 20th centuries, that Muslims were quaint and relatively harmless Orientals of a bygone culture, much like any other non-Western culture still holding on to past traditions; coupled with the Wilsonian optimism that given enough time and Western intrusion, these quaint Orientals would Westernize (for, after all, the measure of man is the Homo Occidentalis, is it not...?).
Then overlaying this, and perhaps growing organically from the same cultural soil, was an increasing cultural standardization of a tendency that has been in the West for centuries (long before "Leftists" even existed, much less Marxists), which blossomed in full force by the middle of the 20th century and has been gaining sociopolitical and cultural traction in the decades since right into this second decade of the 21st century where we find ourselves -- Politically Correct Multi-Culturalism -- whose central axiom is what Lawrence Auster called his "First Law of Majority-Minority Relations". As Muslims have been unfolding their global revival of Islamic jihad pre- and post-911, the West has responded with a reboot of Auster's First Law.