Les Gelb helped usher in the post-doctrinal phase of U.S. foreign policy. Les was instinctively pragmatic and keenly aware of the vicissitudes of our globalized world, and this made him loath to subscribe to any fixed notion of what it would take to advance U.S. interests or foster a more stable and prosperous world. His distaste for bombast and his skepticism about generalizations and sloganeering led him to distrust assertions that our world could be explained or transformed by any single idea. He saw concepts such as “hard power,” “soft power,” “smart power,” “leading from behind,” “preemptive war,” “the responsibility to protect,” and even “liberal interventionism” as ideas that could be productively deployed in particular situations, but that would do more harm than good if adopted as catch-all solutions to complex and changing problems. To Les, such concepts represented provisional approaches, rather than eternal maxims or fixed belief systems.

Les recognized that a world in which power has become diffuse and protean—in which blistering technological change is a constant and in which attitudes and value systems persistently compete—was not a world that would submit to absolutes. He found arguments about competing grand schemas wearying and mostly futile.

Les’s own twenty-first century foreign policy treatise, Power Rules, reflects above all a conviction rooted in the danger of reifying conviction. Les’s precepts for wielding power are less “rules” than truths—observations, insights, questions, and pieces of advice that may help leaders and policymakers better grasp the perils before them, avoid pitfalls, take better advantage of the tools at their disposal and make more informed, farsighted, and clear-headed decisions.

Les’s view of the world was informed by his awareness of his own fallibility. He warned against excessive reliance on fashionable theories and slogans because he understood their allure—and knew that he too was susceptible. In a typically blunt and candid 2009 assessment, he declared that his own initial support for the 2003 invasion of Iraq “was symptomatic of unfortunate tendencies within the foreign policy community, namely the disposition and incentives to support wars to retain political and professional credibility. We ‘experts’ have a lot to fix about ourselves . . . We must redouble our commitment to independent thought, and embrace, rather than cast aside, opinions and facts that blow the common–often wrong–wisdom apart.”

Les was innately skeptical of claims to genius, revelation, or even grand strategic insight, and as a leader of institutions and a mentor to young foreign policy hopefuls, he was a persistent questioner of dogma and careless thinking. Whenever a new proposal was enthusiastically presented, Les would insist that its proponents convincingly explain why, if the proposal was so compelling, it had not been pursued previously. What had stood in the way, both practically and conceptually? He consistently rebuked Panglossian thinking, and frequently reminded his protégés that there’s no such thing as a free lunch: Every move involves trade-offs, and those trade-offs need to be acknowledged and honestly evaluated. “Oh,” he’d say blandly, “you propose that the United States pull all troops out of Iraq immediately, and create a stable, democratic, and prosperous Iraq? How exactly do you plan to do that with no military presence on the ground? Whose money will you use to promote democracy and stability? What will you do to persuade Congress to allocate those resources? And what makes you think they’ll agree with you?” His questions were relentless. “What door will you go through first? And then what? And then what?”

Being questioned by Les was not an entirely comfortable experience, but this, perhaps, is one of his most enduring legacies: his constant admonition that what is comfortable is rarely the same as what is right or wise. Les prepared his protégés for a world where easy answers would elude, American power would often fall short, moral certitude was unavailing, and little remained absolute. Learning from Les was good preparation for an instant era in which once-reliable constants like American values, the durability of democracy, the trustiness of institutions, the sanctity of alliances, and even his vaunted “common sense” have all been cast into doubt.

Those who learned under Les realize that the escape route from the current maelstrom lies not in weighty pronouncements or newfangled worldviews. Les would instead urge—as he always did—the sure-handed deployment of the basic building-blocks of influence in international relations: near-term strategies with clear objectives, strong interpersonal relationships, creativity, open-mindedness, curiosity, information, daring, foresight, effective persuasion, and operational competence. He would have insisted that we could not theorize our way out of this morass, but rather would have to fight our way out of it choice by choice, decision by decision.