President Trump announced that H. R. McMaster will be his new National Security Adviser, replacing Michael Flynn.

Removing Flynn was already addition by subtraction, and adding one of the military’s foremost intellectuals will strengthen the administration’s foreign policy team. But how much influence McMaster will have remains to be seen.

To counterinsurgency wonks like me, McMaster is a living legend. In Iraq, he stabilized Tal Afar, a city of 200,000, with 5,200 soldiers.

For states fighting an asymmetric campaign against non-state actors, as in post-Saddam Iraq, there are essentially two available strategies: counterterrorism (CT) and counterinsurgency (COIN).

CT is terrorist hunting. Locate enemies and kill or capture them. But insurgencies are fluid, willing to flee areas where the military is concentrated. Critics deride CT as whack-a-mole, since the military kills insurgents in one place only for them to pop up elsewhere.