In the midst of the vitriol flying between Washington and Pyongyang, a number of voices have emerged to assure the world that war is indeed unlikely. The leadership of both nations, they explain, has many rational, well-informed actors who recognize the potentially catastrophic consequences of a second Korean War, and hence will avoid crossing any of the critical lines that might take us there.

Theoretically, the voices are correct. Unfortunately, modern history shows that decisions for war are not made in theoretical circumstances, nor rooted in rational calculation. They are instead made by flawed individuals driven by emotion, miscalculation and misperception, and influenced by others with their own agendas who sit far from the chain of command.

The great danger of the current crisis is thus not that decision-makers in Washington and Pyongyang will deliberately weigh the costs and benefits of another Korean War and decide it is worth pursuing. It is instead that a sudden and unexpected moment triggers a hasty and emotional decision that leads both sides down a tragic path from which there is no return.

The 1962 Cuban missile crisis demonstrates how easily foreign policy crises can spin out of control despite the best intentions of those at the top of the decision-making process. Most Americans celebrate the wisdom demonstrated by President John F. Kennedy and Premier Nikita Khrushchev, who acted with restraint while working to avoid what surely would have been a devastating clash. Few Americans, however, understand how close to war we actually came despite their efforts, as the actions of less well-known figures and the inevitable chaos of unanticipated circumstances threatened to undermine their best intentions.

On Oct. 27, 1962, Soviet forces shot down an American U-2 over Cuba, killing the pilot, Maj. Rudolf Anderson. Khrushchev had given specific orders not to fire on American targets unless war had started, but the Soviet commander on the ground, Gen. Stepan Naumovich Grechko, decided to shoot it down on his own authority. American officials had earlier agreed that such an action would probably evoke an American military response against Cuba, but Kennedy wisely chose to delay such a response.

That same day, American ships were harassing a Soviet submarine in the Caribbean. With no contact from Moscow and unsure of the current status of events on land, the captain, Valentin Grigorievitch Savitsky, ordered the launch of a nuclear torpedo. Only the opposition of his second-in-command prevented an act that surely would have sparked massive retaliation.

In the end, the Cuban crisis was resolved peacefully. But the fact that the world came perilously close to nuclear conflict because of actions taken by individuals outside of the world’s capitals and based on erroneous assumptions should be a sobering warning for those who minimize the current dangers.

The path to other recent conflicts also demonstrates that the road to war seldom runs through an informed assessment of facts on the ground. In June 1950, North Korean forces swept over the 38th parallel, sparking the Korean War. Soviet Premier Joseph Stalin had earlier rejected Kim Il Sung’s request to launch an attack against the South. But he soon changed his mind, in no small part because of a mistaken belief that the United States would probably not intervene, and because of Kim’s unmerited assurances that massive indigenous backing from the South would ensure a quick victory before President Harry Truman could react if he chose to do so.

Likewise, the American role in the Vietnam War exploded after the alleged second Gulf of Tonkin attack on Aug. 4, 1964. We know now that this attack never occurred, but American military and political leaders believed that it had, and President Lyndon Johnson used it as an excuse to obtain the functional equivalent of a declaration of war. In neither of these cases were the critical decisions for war made as part of a sober and thorough assessment of accurate evidence. And yet, war came nonetheless.

The current standoff in Korea seems particularly ripe for such an unintended conflict. A long history of rivalry has predisposed each side to read the worst possible motives into the other’s actions. Official lines of communication between the two are virtually nonexistent; at the moment, the United States doesn’t even have an ambassador in South Korea. The two leaders are inexperienced and emotional, with a tendency to personalize strategic matters and unleash bellicose rhetoric that just heightens tensions throughout the region. North Korean defectors warn of Kim Jong Un’s desperate and unyielding commitment to his nuclear program, which he sees as critical to the preservation of his regime, and of the growing doubts about his government at home. And the North has launched a number of limited but deadly military operations against the United States and South Korea over the past decades, ranging from the attack on the USS Pueblo in 1968 to the attack on the Cheonan in 2010, but has never faced serious retribution for them, probably encouraging Kim to trust in the safety of a limited strike that could be a critical first step.

Recent history thus suggests that the greatest danger we now face is not that Donald Trump and Kim will decide to go to war, but that isolated individuals who most have never heard of, operating within the inevitable chain of mistakes and miscalculations that are the by-product of human weakness and exigent circumstances, will decide for them. This concern seems particularly acute this week, as the United States and South Korea hold their annual Ulchi Freedom Guardian drills, which for the first time might include a nuclear war game and which the North has condemned for “adding fuel to the fire.” “No one can guarantee that the exercise won’t evolve into actual fighting,” they noted ominously.

The lessons of history suggest that in such circumstances, policymakers on both sides cannot just rely on good intentions. They need instead to be cognizant at all times of the heightened risks inherent in such situations, act with significant restraint at even the slightest alleged provocation and impose institutional checks at every level to prevent a small misstep from spiraling out of anyone’s control.