This article presents statistical estimates of ISIL support in the Muslim world, based on Pew data covering 42 percent of the total global Muslim population on favorability of four terror organizations, to be well compared with ISIL: Hamas, Hezbollah, the Taliban, and al Qaeda, and the favorability of suicide bombing. It is assumed that these data (average support rates) reflect the true, but unknown, rates of ISIL support, which will be at somewhere around 17 percent of the entire global Muslim population. The article analyzes mechanisms that contribute towards ISIL favorability, such as anti-Americanism, the hatred of the State of Israel, and the advance of violent Islamism. Finally a comparison of the evolving terror scene with the conflict in Northern Ireland is also outlined.