Orson Scott Card has an interesting historical analysis up.
I’ll cut to the chase here, but it the piece should be read in it’s entirety.
Here’s how it happens: America stupidly and immorally withdraws from the War on Terror, withdrawing prematurely from Iraq and leaving it in chaos. Emboldened, either Muslims unite against the West (unlikely) or collapse in a huge war between Shiites and Sunnis (already beginning). It almost doesn’t matter, because in the process the oil will stop flowing.
And when the oil stops flowing, Europe and Japan and Taiwan and Singapore and South Korea all crash economically; Europe then has to face the demands of its West-hating Muslim “minority” without money and without the ruthlessness or will to survive that would allow them to counter the threat. The result is accommodation or surrender to Islam. The numbers don’t lie — it is not just possible, it is likely.
The process is rooted in specialization. I’ve been fiddling around the periphery and never put the pieces together as has Card.
There’s a corollary issue that he doesn’t address squarely and that’s how the transnational bent of business has directly weakened the west by weakening our military capability.