3) What’s the best way to respond to Islamist terrorism?

McMaster and Trump have very different understandings of the right strategic response to terrorism. Trump has lamented that the United States did not take Iraq’s oil and quipped that terrorists’ family members should be targeted. By contrast, in Iraq, McMaster developed counterinsurgency doctrines in which soldiers worked not just to destroy targets but to protect populations and win local communities’ hearts and minds.

Trump speaks of terrorism and Islam as if they were nearly synonymous. On the record, he has stated that “Islam hates us” and that there is “tremendous hatred” within the religion itself. McMaster discusses Islam in a manner consistent with the tactful U.S. foreign policy formulation that’s been used over the last decade. He refers to militant Islamists with the moniker “salafi jihadists” — referring to the Islamist ideal of restoring a bygone glory. McMaster says such practices have a “perverted” and “irreligious interpretation” of Islam.

For McMaster, the sources of Middle Eastern angst are primarily political. He explains the Afghanistan and Iraq insurgencies through a narrative of grievances exacerbated by “ethnic, tribal, and sectarian polarization.” As a student of the 19th-century German military thinker Carl von Clausewitz, McMaster is wary of promising fast and cheap victories.