But since the arrival of Donald Trump in the White House, a bad situation has become far worse. North Korea has accelerated its missile testing and Trump has vowed a military attack against North Korea if it threatens the U.S. or its allies.

The risk of conflict through miscalculation by either side is now as severe as the tense days of October 1962, when the U.S. and the Soviet Union nearly went to war over the deployment of Soviet missiles in Cuba. Just as was the case in 1962, even a small action or wrong word could lead to war.

Now, as was the case then, events could easily escalate to the nuclear level. Each side must refrain from further threats and taunts and open a direct, private, and high-level diplomatic channel of communication.

In October 1962, President John F. Kennedy carefully calibrated and coordinated all U.S. government messages and signals toward Moscow so that America’s intentions were clear. He exchanged direct, private messages with his Soviet counterpart, Nikita Khrushchev, to seek a way out of the crisis. Kennedy was careful not to rule out compromises that would later prove essential in removing Soviet missiles from Cuba and ending the standoff.

The lack of discipline and coordination shown by the Trump administration, however, has increased the risk in this situation. Worse still, U.S. Ambassador to the United Nations Nikki Haley and others have already knocked down a Chinese proposal to deescalate tensions whereby North Korea halts further nuclear and missile tests in exchange for the U.S. pausing certain military exercises that North Korea sees as particularly threatening.

Given that no one has likely ever told North Korean leader Kim Jong Un “no” in his life, and given that Trump has never been known to publicly back down in a feud, it is unlikely they are capable, by themselves, of finding a diplomatic off-ramp.

An outside diplomatic intervention is in order. For example, the UN secretary general could convene an emergency, closed-door meeting with senior leaders from the members of Six Party Talks (China, North Korea, Japan, Russia, South Korea, and the U.S.) and to initiate a serious dialogue designed to lower tensions and address issues of mutual concern. Alternatively, Trump could authorize a representative to meet with a senior representative of Kim in Beijing to work out a plan to calm the situation.

Months ago, the Trump administration said its North Korea policy would involve “maximum pressure and engagement.” Since then, we’ve seen pressure, reckless rhetoric, and threats—but no engagement. The history of the nuclear age has shown that smaller states, even those without nuclear weapons, are not easily intimidated by U.S. nuclear threats. North Korea is no exception. Now we have a major security crisis that could spin out of control at any moment. Millions of lives in the Koreas and Japan are at risk.

It is past time for a direct U.S.-North Korea dialogue, without preconditions, that sets a new course—toward a negotiated or brokered agreement that addresses the concerns of the international community and the security concerns of North Korea. Such a course begins with an immediate halt to further nuclear test explosions and intermediate- or long-range ballistic missile tests and any military exercises that could be interpreted to be practice runs for an attack.

As Kennedy said following the Cuban Missile Crisis: “Above all, while defending our own vital interests, nuclear powers must avert those confrontations which bring an adversary to the choice of either a humiliating defeat or a nuclear war.”

Now is the time to back away from the edge of a conflict that could escalate to the nuclear level all too easily.

Daryl G. Kimball is the executive director of the independent, nongovernmental Arms Control Association.