As a result, when the Soviets overstepped themselves and provoked crises over Berlin and then Cuba, they panicked when the Kennedy administration showed a willingness to go to war rather than give in to their demands. In both cases, Moscow quickly sought to defuse the situation as fast as possible, even accepting humiliating conditions to avert a war they knew they would lose.

Like the Soviet Union early on in the Cold War, even a nuclear-armed Iran would be vastly outmatched by the U.S. strategic arsenal. Unlike the Soviets, the Iranians can’t ever hope to match the U.S. Thus, in any crisis, American negotiators will have the upper hand and should be able to compel the Iranians to back down quickly, even accepting significant reversals to avoid a war.

On past occasions when Iran crossed an American red line and was at risk of a U.S. military response — during the Tanker War in 1988, after the Khobar Towers attack in Saudi Arabia in 1996 and after the U.S. invasion of Iraq in 2003 — the Iranians have backed down quickly and even made humiliating concessions of their own (such as ending the Iran-Iraq War and agreeing to suspend uranium enrichment) to avert an American attack.

A third observation from the Kennedy era is that communication is critical. Misperceptions are inevitable in international relations, and the fear conjured by nuclear weapons only adds to that risk. Kennedy resisted demonizing Khrushchev, seeing him instead as a mercurial leader prone to taking big gambles to try to address the challenges he faced. Although Kennedy’s sense of Khrushchev was broadly correct, he and the U.S. government in general still tended to misunderstand the Soviet leader’s goals and thinking.