Don't comfort yourself with talk of a 'preemptive' strike on North Korea

As the Trump administration continues to leave open the possibility of military conflict with North Korea, it’s time to talk about the concept of preventive war. A recent poll noted that 46 percent of Republicans favored a “preemptive” strike on North Korea. This is a careful smudging of the language of war, and the difference matters.

A preemptive strike is one undertaken in the face of an immediate threat. Much like throwing the first punch at a mugger who is about to lunge at you, preemption is self-defense just ahead of an obvious attempt to do harm. The clearest case of preemption in modern history was the 1967 Arab-Israeli war, in which the Israelis attacked enemy forces as they were massing and preparing to move.

Preventive strikes, however, are conducted against possible, rather than immediate, dangers. These are actions taken far in advance of a material threat, a kind of prophylaxis against a gathering danger. Sometimes called “strangling the baby in the cradle,” preventive war is meant to head off a future peril. Examples of this kind of attack are when the Japanese tried to sink the U.S. fleet at Pearl Harbor to get it out of the way ahead of a possible war, or when the Germans invaded Norway in 1940 to foreclose its use to the allies in the future.

Voters likely have no idea of the difference. But when it comes to making war, there are moral and strategic distinctions that Americans should consider. A preemptive strike is acceptable both as a matter of tradition and law in international affairs because it is meant to limit damage from an imminent threat. What “imminent” means is a matter of debate and is usually a matter for lawyers and scholars.

The standard language comes from an 1837 event that established the baseline for preemption, the “Caroline test.” Named for an American merchant ship sunk by the British after charges it was aiding anti-British rebels across the Canadian border, this test allows action only in the face of danger that is “instant, overwhelming, and leaving no choice of means, and no moment for deliberation.”

In the 21st century, “imminence” is a difficult concept, and those who argue for striking North Korea sooner rather than later have a point. We no longer live in a time when armies mass and send clear warning. A single missile might be harder to detect than a million men gathering on the demilitarized zone. The problem, of course, is that once we leave aside actual threats for notional threats, there is no limit to the blank check we may write ourselves. If we believe we must strike North Korea next year, why not today?

In the 1950s, for example, debate swirled in the United States over destroying the Soviet Union and its new nuclear bombs, with one of the advocates for preventive war, renowned mathematician John von Neumann, remarking, “If you say why not bomb them tomorrow, I say why not today? If you say today at five o’clock, I say why not one o’clock?”

This leads to the self-proclaimed right to wage war at will, which is why preventive war has never been acceptable in international affairs. (Indeed, the invasion of Norway was among the many charges for the which the Nazi leaders were hanged.) The moral stain of preventive war is one few nations can sponge away, as the United States learned after its preventive war in Iraq.

Moreover, there are huge strategic costs and risks to preventive war. Aside from placing our allies in South Korea and Japan in immediate danger from a war they may not want and for which they may not be ready, preventive war is a destabilizing policy. A world of states engaging in preventive strikes would be a world of constant war, as the most powerful states, to take a line from Thucydides and his study of one of the earliest preventive wars in ancient Greece, would “do what they can while the weak suffer what they must.”

Yet, there may come a time when North Korea is so close to a working nuclear intercontinental ballistic missile that the United States would be justified in running the moral and strategic risks of striking first. The regime in Pyongyang, its aging generals and the weird boy king who leads them have made clear their intention to harm America and are determined to gain the means to do so. The judgment about when to go to war and risk the lives of our sons and daughters, as well as the lives of the people in the region, will at some point have to be made on a razor’s edge, or should be.

In the meantime, Americans should not comfort themselves with talk of “preemption.” That is not what the administration currently is describing. And if a preventive war is unavoidable, despite our best efforts, we should be able to say that we have walked into it with clear eyes and a full understanding of what we’re doing and why. We owe that to our citizens, as well to the many among our allies who will be killed and wounded should that day come.

Thomas M. Nichols is a professor of national security affairs at the U.S. Naval War College and an adjunct professor at the Harvard Extension School. His latest book is “The Death of Expertise: The Campaign Against Established Knowledge and Why It Matters.” Follow him on Twitter @RadioFreeTom. The views expressed are his own.