If these activities all test the theory that threats of violence can deter an adversary from engaging in violence of its own, they also test a concept Jervis articulated several decades ago, in the context of the Cold War nuclear standoff. His central insight in the 1978 paper “Cooperation Under the Security Dilemma,” was that “many of the means by which a state tries to increase its security decrease the security of others.” It’s not hard to find examples of this in East Asia. U.S.-South Korea joint military exercises are ostensibly designed to increase those countries’ security, but North Korea sees them as decreasing its own. American missile defenses on the Korean peninsula, meant to blunt the threat of the North’s missiles, have radars that look to China like they could help America spy on China’s own weapons, threatening Beijing’s ability to defend itself. North Korea itself maintains its missile development is to defend against the kinds of attacks the U.S. is now hinting at.

I recently spoke to Jervis about the security dilemma in East Asia, and the grand international-relations experiment of the Trump presidency. A condensed and edited transcript of our conversation follows.

Kathy Gilsinan: Walk me through how the security dilemma is working in the context of the U.S. and North Korea.

Robert Jervis: Let’s start with North Korea’s explanation for its missile program. It argues really that it is defensive and it doesn’t want to intimidate anyone else, except as that’s necessary for its defense. And after all, the U.S. had threatened to drop nuclear bombs on [North Korea] during the Korean War, and has implicitly or explicitly made nuclear threats in periods of tension. Secretary Tillerson has just threatened a pre-emptive strike, and while we see this only as a last-ditch defensive measure, I’m sure North Korea sees it quite differently.

North Korea argues and may believe that the reason it needs nuclear weapons and the missiles is to make sure that the U.S. doesn’t attack or, more likely, overthrow the regime. [The North Koreans] did explicitly point out after the Iraq invasion that the U.S. does overthrow regimes it doesn’t like, as long as they don’t have nuclear weapons. So there is a legitimate defensive rationale. Most people who know North Korea better than I do say that this isn’t the entire story, that North Korea [also] wants to exert greater influence in the region, to intimidate South Korea. Crazy as it seems, all the experts say that the whole Kim dynasty believes Korea will be unified—under North Korean auspices, a unified North Korean regime. As usual there are a mixture of motives and drives, offensive as well as defensive. But I think it’s easy for us to forget that there is a defensive aspect to this.

The next layer is that sometimes U.S. policy has sought to ameliorate any legitimate fears North Korea would have, and even the Bush administration finally decided, after a lot of internal debate, that we would reassure North Korea and make a promise that if negotiations were successful we would not seek to attack the country. Victor Cha [adviser on North Korea to President George W. Bush] tells the story in an article that he was tasked to tell the North Koreans this, and we really thought it would have some impact on them. These were verbal promises, but they represented a real policy change. The Russians went up to the North Koreans to say, essentially, we wanted this kind of guarantee during the Cold War and the Americans didn’t do it. Why this didn’t work not entirely clear; maybe the North wasn’t really worried, or it is the credibility problem. [Cha writes: “It seemed to me at the time that the DPRK finally received the security guarantee and the end to ‘hostile’ U.S. policy that they had long sought. Yet, after holding this out as a precondition for progress, in subsequent rounds of negotiations they proceeded to brush this off as a meaningless commitment, a piece of paper that guaranteed nothing for North Korean security.”]