If I had to pinpoint the single most important reason recent U.S. train-and-equip efforts have failed, I’d say it’s this: We consistently fail to understand that other people want to pursue what they see as their interests and objectives, not ours. We go into complex foreign conflicts with a profound ignorance of history, language, and culture; as a result, we rarely understand the loyalties, commitments, and constraints of those we train. Sure, we undertake “vetting,” but it’s remarkably shallow: If there’s no evidence of actual collaboration or affiliation with groups we don’t like, and no evidence of participation in egregious human rights abuses, a trainee or military unit is good to go.