In mid-March, the United States and South Korea began conducting a joint military exercise. The nine-day exercise was a command post exercise, meaning it took place mainly via computer simulations. This represents a significant departure from the usual practice. Since the end of the Korean War, the U.S. and South Korean militaries have participated in joint military exercises designed to provide training to and enhance the interoperability of the two nations’ forces. These exercises are common; in fact, South Korea participated in joint exercises on approximately one-third of all days between 1997 and 2016. Since the 1970s, the U.S.-South Korean joint exercise program has included annual springtime exercises that bring U.S. and South Korean troops together to practice field maneuvers.

The first of these springtime exercise series was “Team Spirit,” which began in 1976. It engaged large numbers of troops—sometimes more than 200,000 at a time—in field maneuvers. North Korea saw the “Team Spirit” exercises as threatening. The exercises reportedly made Kim Il-Sung visibly angry, and they were slandered in North Korean media sources. In the lead-up to the negotiations for the 1994 Agreed Framework, the “Team Spirit” exercises were twice cancelled.

After the Agreed Framework was adopted, “Team Spirit” was replaced with a command post exercise series—which has since undergone several name changes—as well as a smaller series of tactical level exercises referred to as the “Foal Eagle” series. After running for more than two decades, the “Foal Eagle” series ended in 2019, when it was replaced by a scaled down version called “Dong Maeng.”

The Trump Administration argued that the exercises were simply aggravating North Korea and that scaling them down was an important concession in the road to denuclearization. Indeed, official North Korean news outlets had characterized the activities as “exercises for a nuclear war” and accused the United States and South Korea of “playing with fire.”

Others, however, have dismissed North Korea’s rhetoric about military exercises as just another example of inflammatory propaganda that has little to do with North Korea’s actual behavior or preferences. Although field exercises were planned for the spring of 2020, they were ultimately cancelled, due to the complications posed by coronavirus. Now, in 2021, the field exercises are altogether gone, replaced with simulations.

This year’s simulations may not have been able to capture as many of the benefits as previous year’s field exercises. Military exercises have a number of objectives. They can enhance military effectiveness by providing training, military readiness by improving planning, and military interoperability by offering opportunities for collaboration between different forces and nations. Some have suggested that the exercises can also serve an important deterrent role. By demonstrating military capabilities, the exercises show adversaries what could befall them if a war were to break out. (Recent research, however, finds that exercises are more likely to escalate tensions than prevent them.) While all types of exercises can serve some of these roles, not all exercises are made equal.

Field exercises are often much larger than command post exercises, and they can involve high-end equipment and complicated maneuvers such as amphibious landings, anti-submarine warfare, and close air support. These features can make field exercises both costly and complex, but as a result, they also provide valuable opportunities for troops to practice important activities.

As a result of their size, field exercises generally provide training to more individuals. Importantly, field exercises often involve training for those at lower ranks who are less to be involved in the sort of joint planning exercises typically done via simulation. In some cases, field exercises can also involve calling up reserves or deploying additional troops and resources. As a result, field exercises can help officers identify logistical challenges and other bottlenecks, then work together to solve them.

Command post exercises, on the other hand, lose many of the advantages associated with field exercises. They’re less visible; they’re smaller; and they generally don’t involve the same equipment. Command post exercises do have some strategic value, though. They can help states work out logistics and resourcing problems, develop joint strategies, plan for contingencies, and create valuable connections between commands that don’t normally operate in close proximity. With the ongoing state of the global coronavirus pandemic, the relatively small size of this year’s command post exercises may allow the two militaries to implement more cautious health protocols and limit the amount of travelling necessary for the exercise to take place.

This unusual year has led to an unusual exercise—and that, itself, may be yet another disadvantage. With the cessation of “Foal Eagle,” the cancellation of last spring’s exercises, and this year’s departure from the standard field exercise format, this year’s exercises aren’t a clear continuation of any regular, recurring series. Recurring exercises have long been central to the U.S.-South Korean relationship. They are often very visible and are heavily covered in South Korean media, where they serve as a strong signal of U.S. commitment to the alliance and take on a confidence-building role. The smaller, less visible nature of this year’s exercises, along with their more tenuous connection to previous exercise series, may make some in South Korea wonder about the continued U.S. commitment to security on the Korean Peninsula. Uncertainty about the Biden Administration’s plans for North Korea may only add to these qualms.

Although this year’s exercises may have some significant disadvantages, they may have at least one notable advantage: They may provoke less anger from North Korea, which has long expressed disdain for the U.S.-South Korea joint military exercises, including the spring field exercises series. New research shows that, when an exercise takes place, North Korea is not only more likely to make threats against the United States and South Korea in its state-run media, but it is also more likely to engage in aggressive behaviors. Moreover, this research shows that North Korea is attuned to the characteristics of the exercises that the United States and South Korea run. Exercises that are more threatening to North Korea’s interests—including larger exercises, field exercises, and recurring exercises—elicit stronger reactions from North Korea than less threatening exercises—such as small, non-recurring simulations.

As expected, North Korea did recently threaten the United States and South Korea with retaliatory measures, but the comments were somewhat more subdued than previous North Korean reactions to the spring exercise series. Kim Yo-jong, the sister of Kim Jong-un, offered both vague warnings as well as allusions to possible diplomatic recourse, such the dissolution of organizations responsible for inter-Korean relations.

These threats weren’t just a reaction to the U.S.-South Korean exercises, however. They came in response to both the recent exercises and the visits of U.S. Secretary of State Antony Blinken and U.S. Secretary of Defense Lloyd Austin to Seoul and Tokyo. It is also common for North Korea to increase its aggressive behavior during political transitions, major diplomatic visits, and other such events.

That North Korea would react as it did is hardly surprising; after all, North Korea makes dozens of threats against its adversaries every month, and joint military exercises and foreign diplomacy are both regular causes of such vitriol. In this case, North Korea’s comments may actually represent a “toned down” reaction—at least compared to previous years’ exercises. Many experts had even expected North Korea to take more a visible, adversarial step—like testing missile technology—ahead of recent events. While this remains a possibility, any such actions would likely be less about responding to recent military exercises and more about communicating resolve to the Biden Administration as it begins to design and implement regional policies.

Lauren Sukin is a Ph.D. Candidate at the Department of Political Science at Stanford University.

Image: Reuters.