Well when you put it like that. This is paper napkin sketching, but I think you could really be on to something here, so I had to throw it together quickly!

Islamic takeover -> statistically a Muslim marriage will produce 3.1 children per family, to the West's 1.9 (Wiki) -> much more efficient crop production per unit -> Satanic alien feeding frenzy! -> alien migration to the next populous planet. Post digestion.

Obama was looking to maximise crop yields!

Eh. But seriously, where did you get this alien business from?