Shortly after Harry Truman’s ascension to the Presidency, in April 1945, he named Dean Acheson to be his Under-Secretary of State. Four years later, at the height of the Cold War, Acheson became Secretary. No individual was more central to, and responsible for, the creation of structures and policies that set the course of American foreign relations from 1945 to the present day.

In October, 1962, the United States and the Soviet Union came close to conflict; this crisis resulted in the establishment of implicit boundaries for waging nuclear confrontation. Not since then has the parameters for the use of nukes become so widely discussed and analyzed. What brought this about was, of course, Russia’s brutal invasion of the Ukraine on February 24th. Largely due to Russia’s continuing failure to defeat Ukraine on the battlefield with conventional weapons, world leaders are forced to contemplate a scenario in which Russia may grasp at a nuclear option to force the Ukranians to accede to their demands. In fact, we may be “present” at the creation of a modified foreign policy paradigm in which nuclear arms has become an acceptable predicate for purposeful inclusion in both tactical and strategic foreign/defense policymaking.

With Pakistan, India, Israel, France, Great Britain, and China, joining the United States and Russia as nuclear powers, it is remarkable that it has taken this long for tactical nuclear diplomacy to become so central to the international dealings of nations. Remember, North Korea, Iran, Egypt, Brazil, and Saudi Arabia, are each waiting for an opportunity to become a member of the nuclear club. The relevant question then becomes, “How to deter or, if that fails, deal with, their use?” The Ukrainian crisis should leave decision-makers little choice but to seriously develop anew, a strategy for dealing with this existential matter.

As policymakers, academics, et al contemplate mass destruction, the conventional use of force must remain as the primary tool for ending this present conflict and applying what we learn now to avoid similar crises. “No first use of Nukes” must, of course, remain in the forefront of the policies of America and its allies. But, in situations like the present one in Ukraine, the key question remains as to how to respond when a nation uses them in a tactical situation. (If they are used strategically, we are in the worst kind of existential situation; a topic for another day.) That we even have to think about this, and the failure to deter–at any level–occurs, should scare us all. Yet, madmen like Hitler, and now Putin, don’t scare easily. The midst of war may not be the best time to debate such matters, but we have no choice given the stakes involved. So I return to Dean Acheson. A careful reading of his memoir, PRESENT AT THE CREATION, provides a wide range of answers as he and his colleagues dealt with one threat after another in the midst of the Soviet Union’s new-found ability to deploy nuclear weaponry.

For those seeking to explore what happened from Hiroshima to the end of the Korean War, read the book. The essential lesson I draw that may be useful in today’s environment is this: “Mutual Assured Destruction” remains the only useful operating deterrent at the strategic level. Tactically, Ukraine has brought us to the necessity for being “Present at the Creation” of a new set of policies that, above all, mandates no appeasement of the aggressor, and a clear and public understanding of what’s at stake as the existential precipice is approached. Be it the establishment of an international-type police force with teeth, and/or a United Nations with the ability to swiftly act in a crisis (which probably means a Security Council absent a Member State’s veto power), the international system can only be secure if we rapidly act to repair it. Everyone’s life, literally, is at stake.