How the US and Soviet Union Pulled Back from the Brink of War
An insider offers a perspective on the Cold War, the Reykjavik summit, and the landmark nuclear weapons treaty that followed.
The new feature film The Brink of War tells the story of the 1986 Reykjavik summit between US President Ronald Reagan and Soviet leader Mikhail Gorbachev during which the two countries considered eliminating their stockpiles of intercontinental ballistic missiles (ICBMs)—by far the largest in the world. General Lee Denson, PhD ’67, led the arms control staff at the Pentagon at the time. In this interview with Harvard Griffin GSAS Communications, Denson discusses the arms control negotiations between the US and Soviet Union before and after the summit, his role in forging the 1987 Intermediate-Range Nuclear Forces (INF) Treaty, and the Cold War’s enduring lessons for leaders today.
Arms Control in the 1980s
Let’s set the stage. You were brought on to run the arms control staff in the Pentagon in the mid-1980s. What was your official title?
Lee Denson: I was the deputy director for international negotiations. I was one of three deputy directors on the Joint Chiefs of Staff (JCS), who served under a three-star general who was the director for plans and policy. To save time, I reported directly to the Chairman of the Joint Chiefs.
Arms control requires a significant amount of attention, and we had nine active negotiations going on simultaneously. President Reagan made it clear he wanted military advice before making any decisions on the issue.
Reagan took a much harder line against the Soviet Union and its expansionism than his predecessors. He did not bring the SALT II Treaty to the Senate for ratification and stated that the US would not abide by it. So, how would you characterize relations between the US and the Soviet Union when you took over the arms control staff at the Pentagon?
Lee Denson: They were tense, but we had learned to coexist peacefully. Reagan’s slogan for arms control was “Trust, but verify.” His staff—including the Arms Control and Disarmament Agency (ACDA), the State Department, and the Central Intelligence Agency—wanted assurance that the Soviets were abiding by the various treaties, and we needed to be able to verify that compliance.
Reagan was determined to secure better arms control agreements because he preferred that to war. His staff informed me that his greatest fear was being awakened at 2:00 a.m. and told that a Soviet ICBM attack was underway, leaving him with only 15 minutes to decide whether to retaliate before many of our own missiles were destroyed in their silos. He wanted to mitigate that threat, so he authorized the Strategic Defense Initiative (SDI), a space-based antimissile system, which thoroughly frightened Gorbachev. They both had pressing issues to work out with one another, which ultimately led to the Reykjavik summit.
[President Reagan’s] staff informed me that his greatest fear was being awakened at 2:00 a.m. and told that a Soviet ICBM attack was underway, leaving him with only 15 minutes to decide whether to retaliate before many of our own missiles were destroyed in their silos.
How concerned were you and the administration about the prospect of nuclear war in the mid-1980s?
Lee Denson: We were less concerned than we had been in previous years because we had developed numerous channels for dialogue and information sharing with the Soviets. As long as those discussions—not only regarding arms control but also daily operations—were continuing, we felt secure. For example, if radar detected an object flying over the pole in Canada, we could immediately communicate with the Soviets at the working level to confirm it was not one of their aircraft. We had built a structure in which we could verify our relations, even if we did not inherently trust them. Furthermore, Gorbachev wanted to reform the Soviet Union and withdraw from Eastern Europe because the occupation was bankrupting them. He genuinely wanted better relations.
The Nuclear Triad and European Missiles
What was the structure of US nuclear forces at the time?
Lee Denson: We possessed a strategic triad comprising land-based ICBMs, strategic bombers, and submarine-based forces, making it extremely difficult for an adversary to eliminate our entire arsenal.
During the Kennedy administration, we developed two theater-range intermediate nuclear weapons that really bothered the Soviets. One was the ground-launched cruise missile (GLCM), which flew at about Mach 0.7 very close to the earth, evading radar detection. The other was the Army’s Pershing II missile. The Pershing II warheads could penetrate deep concrete and steel, potentially targeting the Kremlin’s underground bomb shelters in Moscow within minutes of launch from Western Europe. When Gorbachev came to power, he desperately wanted to eliminate that threat. In response, the Soviets had developed the SS-20, but it was essentially a “city buster”—an anti-population weapon with poor accuracy.
What was the understanding at the Pentagon regarding the potential result of a full nuclear exchange between the US and the Soviet Union? Was there a notion that it would result in anything less than complete catastrophe?
Lee Denson: The common perception was exactly that. A Soviet strike would not just target our ICBMs; they would have to hit our bomber bases and attempt to destroy our submarines. The entire purpose of the triad was to make it virtually impossible to destroy our nuclear capability completely. But still, nuclear war would effectively mean the end of civilization.
Verification and the Path to Reykjavik
Was there a shift in the administration’s approach to arms control when Soviet leadership transitioned to Gorbachev?
Lee Denson: Yes. We began pursuing more stringent verification methods. One significant measure was the agreement to fly over each other’s territory to photograph military bases. However, our primary focus was on-site verification using X-ray technology. The verification measures eventually established in the INF Treaty were incredibly stringent.
The Air Force Chief of Staff and my strategic staff agreed with me that this tentative agreement [that came out of Reykjavik] was unacceptable. . . . The JCS did not want to eliminate a leg of the [strategic nuclear] triad, let alone the one with the fastest and largest potential retaliation.
How confident were the administration and the military in their ability to monitor Soviet nuclear forces?
Lee Denson: We were quite confident, but there was a faction—particularly within ACDA—that did not trust the Soviets at all. If the Soviets appeared to push the limits of earlier strategic arms agreements, this group would advocate for canceling the treaties entirely. However, Reagan preferred to take counsel from State Department officials and others stationed abroad who knew the Soviets personally, as well as from the military regarding our capabilities.
In May 1986, only months before the Reykjavik meeting, the Reagan administration discontinued adherence to the SALT II Treaty signed by President Jimmy Carter and Soviet leader Leonid Brezhnev in May 1986. What was the problem with the agreement?
Lee Denson: Our satellites had detected some Soviet violations of the SALT II Treaty. The suspicious element within the administration, including some civilians in the Office of the Secretary of Defense, magnified these breakouts and argued that we could not trust the Soviets, urging the cancellation of the treaty.
During my tenure, there was a constant competition for priority between the negotiating team for INF and the team for the Strategic Arms Reduction Talks (START). Top-level officials had limited time for arms control. As Nancy Reagan famously put it during a meeting of arms control directors, “Let’s get one for the Gipper.” We had to choose which negotiation would receive priority so senior leaders could fully grasp the details and confidently agree to a treaty.
And the INF Treaty ultimately received that priority?
Lee Denson: Yes. The START treaty was far more difficult. It involved more weapons, greater variety in weapon types, and much higher stakes. Militarily, the INF Treaty was actually a bad deal for the US. The Soviets were absolutely delighted to trade their inaccurate SS-20s for the elimination of US systems that frightened them so much. I communicated that to Admiral William J. Crowe, chairman of the Joint Chiefs of Staff. But Crowe was thinking more strategically. He believed Gorbachev was a Soviet leader we could work with and decided to give the treaty a chance.
The Reykjavik Summit
How much did you know about the October 1986 Reykjavik summit before it happened?
Lee Denson: You had to be sworn into a special compartment to know what Reagan intended to achieve. A three-star general, serving as a special assistant to the Chairman of the JCS, attended the summit without being fully briefed.
How close did the US and the Soviets come to eliminating nuclear weapons at Reykjavik?
Lee Denson: Toward the end of the summit, the general called me and said that Reagan had proposed to draw down all strategic ballistic missiles (ICBMs) and that Gorbachev had accepted. But Gorbachev also demanded the US restrict SDI to research—basically, keep it in the lab—for a decade. Reagan felt that SDI could relieve the president of the pressure to decide whether to launch a strike on short notice and with incomplete information. He thought it could have a calming influence. So the summit ended without a signed treaty.
What happened next?
The Air Force Chief of Staff, General Larry Welch, and my strategic staff agreed with me that this tentative agreement was unacceptable. The US had a significant advantage in the number and accuracy of ICBMs, which the Soviets realized. (Hence their gambit to change the strategic balance in the Cuban Missile Crisis.) On the other hand, the Soviets had an advantage in the number of strategic bombers, and we had drawn down most of our anti-aircraft batteries and radar sites by then. The JCS did not want to eliminate a leg of the triad, let alone the one with the fastest and largest potential retaliation.
I immediately worked my way through the chain of command. I managed to reach Admiral Crowe, who was flying to New York City. He initially thought the agreement was acceptable, but as a former diesel submariner, he was not deeply familiar with the strategic balance. He directed me to the acting chairman of the JCS, the Marine Corps Commandant, who then took me to see Secretary of Defense Caspar Weinberger.
Weinberger was alarmed and asked the JCS to study the tentative agreement and come up with a response quickly. We convened at the Chairman’s quarters on a Sunday afternoon, a rarity, and General Welch agreed that we needed to walk this potential agreement back. Thanks to Reagan’s respect for military advice, we were able to.
So, was the Reykjavik summit a failure? Was it a bad idea?
Lee Denson: It was a bad idea initially because the right experts were not consulted. However, Reykjavik effectively became the beginning of the end of the Cold War. It convinced Gorbachev that the US, under Reagan, genuinely sought peace and had no intention of starting a war. Once we agreed to the INF Treaty, Gorbachev felt secure enough to abandon the defense of Eastern Europe.
Negotiating the INF Treaty
What was your role in negotiating the INF Treaty?
Lee Denson: I oversaw all nine active negotiations, but I spent the most time on INF. Having been stationed in Europe for 12 years, I had a good grasp of the operational environment. The treaty covered all weapons with ranges between 500 and 5,000 kilometers. I initially opposed total elimination, arguing we should retain a portion of our INF arsenal to ensure Soviet compliance. In fact, a skeptical official within our administration—nicknamed by us “the Prince of Darkness”—proposed total elimination to Reagan, assuming the Joint Chiefs would never agree to it, thereby sabotaging the treaty. Crowe outmaneuvered him by agreeing to the complete elimination, and the other chiefs followed his lead.
Do you now believe the INF Treaty was a good idea?
Lee Denson: Yes, it was. Crowe’s strategic vision was correct. Militarily, we traded our superior weapons for their inferior ones, but strategically, it proved to Gorbachev that we wanted peace. After the treaty was approved by Congress in early 1988, the Cold War rapidly wound down, culminating in Gorbachev withdrawing Soviet troops from Eastern Europe.
Currently, we seem to lack substantive arms control negotiations. Today’s adversaries are actively seeking to expand their influence—Putin through military force in Europe, and Xi Jinping through unequal economic and infrastructure deals in South America and Africa. We must engage from a position of strength rather than pursuing backward strategies.
Lessons for Today
With increased tensions between the US, Russia, and China, what lessons from the end of the Cold War apply to great-power negotiations today?
Lee Denson: The primary lesson is that negotiations must actually happen. Currently, we seem to lack substantive arms control negotiations. Today’s adversaries are actively seeking to expand their influence—Putin through military force in Europe, and Xi Jinping through unequal economic and infrastructure deals in South America and Africa. We must engage from a position of strength rather than pursuing backward strategies.
Finally, the US has been trying to curb Iran’s capacity to produce a nuclear weapon for years now. As a seasoned arms control negotiator and career military officer, what is your assessment of that effort?
Lee Denson: I fear it is almost too late for negotiations. The [Joint Comprehensive Plan of Action negotiated in 2015, from which the US withdrew in 2018] was an extraordinary diplomatic achievement. It was incredibly one-sided in our favor, with the permanent members of the United Nations Security Council and Germany uniting to impose highly intrusive verification on a medium power. It took immense international coordination and sanctions to achieve.
Today, Iran exerts significant control over the Strait of Hormuz, forcing our close Arab partners in the Gulf to build vulnerable pipelines just to bypass the strait, which will ultimately drive up the global cost of exports like oil and fertilizer. By abandoning the original agreement, we have inadvertently empowered Iran.
