Editor’s note: On Aug. 14, nearly two months after the original publication of this Deep Dive, reports surfaced that North Korea received Soviet-era technology from a facility in Ukraine that expedited the construction of its intercontinental ballistic missiles. As we determine the veracity of the reports, we republish our own assessment of Iran and North Korea, which have also allegedly helped each other advance their respective weapons programs.
Remember Iran? The prospect of war with North Korea has made it easy to overlook this other nearly nuclear power that was until recently the object of Washington’s nonproliferation efforts. Tehran was dead set on developing a nuclear weapon, but it agreed to halt its program in 2015 after extensive negotiations with the United States. Granted, the rise of the Islamic State, a common enemy of the United States and Iran, and years of economic attrition wrought by international sanctions forced its hand. Still, Iran has co