Fears arise that suspension of US-South Korea military exercises may have dangerous repercussions

August is usually a busy time of year on South Korean military bases. As commercial and military planes arrive throughout the South carrying United States military personnel by the thousands, barracks fill to the brim and troops spill into nearby hotels.

For two weeks, from sunrise to sundown and through the wee hours of the night, the bases typically buzz with the comings and goings of soldiers, sailors, airmen and marines all there for the same reason: to practise for the possibility of war with North Korea.

This year, however, the barracks have been empty, and business on bases has continued as usual, after the suspension of the Ulchi Freedom Guardian (UFG) exercise, which traditionally brings together some 70,000 US and South Korean troops each autumn.

For decades, military commanders and diplomats have touted grand-scale exercises like UFG as pillars of the US-South Korean alliance, citing military training and readiness as primary tools of deterrence against the North Korean regime.

It’s a message Pyongyang has received loud and clear, historically responding with streams of colourful invective: “The work of crazy war maniacs,” North Korean state media said last year.

The extent to which North Korea views the exercises as threatening is up for debate, but there is no doubt that Pyongyang – along with Beijing, its primary backer – would like to see a reduction or wholesale departure of the 28,500 US troops deployed on the peninsula.

Experts say that China and especially North Korea likely regard the cessation of military exercises as a move in this direction. That’s why North Korean leader Kim Jong-un came to his meeting with US President Donald Trump in Singapore in June with the joint exercises on his agenda.

When Trump, after that meeting, announced the indefinite suspension of major exercises – calling them “provocative” and suggesting that they were an obstacle to denuclearisation – his words seemed to take South Korea and his own Defence Department by surprise.

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But officials in Seoul and Washington quickly aligned with him, leading to this coming autumn as the first without a major bilateral exercise in more than four decades.

Government statements in both the US and South Korea have played down the suspension’s potential impact on military readiness and effectiveness.

Defence experts, however, warn that the move could lead to the deterioration of crucial relationships and expertise. Further, with the present thaw in tensions still fresh – and at a time when denuclearisation in the North is far from assured – they warn that the UFG cancellation might play too much into Kim’s hands.

“I continue to believe suspending the exercises was a mistake,” said James Stavridis, a retired US Navy admiral who served as Nato’s supreme allied commander from 2009 to 2013. “North Korea benefits greatly from doing so because of a significant degradation in US and [South Korean] war-fighting readiness.”

Stavridis, who now leads the Fletcher School of Law and Diplomacy at Tufts University in Boston, Massachusetts, has been an outspoken critic of the Trump administration’s decision, describing the suspension of military exercises as potentially negligent – and something that could lead to an otherwise preventable loss of life in the event of conflict.

Ulchi Freedom Guardian – named for a seventh century Korean general who defended the peninsula against invasion from the north – was first convened, under a different name, in 1976.

While day-to-day military operations are largely characterised by meetings, paperwork and logistical concerns, US and South Korean military leaders say that, over the decades, exercises like UFG have provided commanders and their staff members with dedicated time to study and execute intricate war plans in a simulated environment.

Together with its partner exercise in the spring, Key Resolve, officials have long positioned UFG as a staple of the US-South Korea mutual defence treaty. As the US Defence Department put it last August, the exercises “help to ensure peace and security on the peninsula, and reaffirm US commitment to the alliance”.

The computer-driven exercises, coupled with troop movements in the field, test everything from basic knowledge of North Korean tactics to the integration of US and South Korean computer networks, intelligence collection and exchange as well as a wide variety of combined military manoeuvres.

Watch: South Korea, US forces hold joint exercises

Placing US and South Korean troops together on bases throughout the South allows for regular informational exchanges and tactical cooperation, but service members with first-hand knowledge of UFG say that much is lost in the absence of large-scale exercises.

“We still keep in close touch with one another,” said one mid-grade South Korean air force officer, who asked not to be named. “But obviously we don’t usually discuss or exchange relevant information on the major war operations.”

The officer said that even operations that might be taken for granted – like ensuring that US and South Korean aircraft operate at safe distances from one another – require extensive communication up, down and across far-flung chains of command, something that is not practised extensively outside the joint exercises.

When it comes to even more complex activities like anti-submarine warfare, long-range air strike coordination and ballistic missile defence, Stavridis said that repetition and rehearsals were indispensable. “These require detailed planning and much practise, especially across the cultural and linguistic gaps in alliance structures,” he said.

Retired South Korean Major General Kim Joong-ro, who led thousands of soldiers as an army division commander and took part in decades of UFG-style exercises, agreed that the opportunity to identify and work through potential points of friction across the alliance structure was crucial.

“Having and maintaining close relationships with our US counterparts is extremely important,” said Kim, now a South Korean lawmaker serving on the parliamentary defence committee. In war, moments of disagreement between leaders who lack an understanding of each other’s diverse perspectives, he added, could lead to catastrophic consequences.

Experts say it is not just military leaders who benefit from time spent with their alliance partners; troops at all levels in the chain of command gain from the experience as well.

On the US side, for instance, June and July mark a period of significant troop turnover. With staff members of all ranks still fresh in their seats come August – including many who lack prior experience in Korea – UFG is well-timed to bring them up to speed, said Bruce Bennett, a senior researcher at the RAND Corporation who specialises in Korean defence policy and exercises.

Many of those new personnel, including some in leadership positions, will serve in Korea for only one year before moving on to other assignments, Bennett said, because of uniquely short tour lengths on the peninsula.

The loss of even one major exercise could thus result in some service members remaining unclear about their wartime roles and responsibilities for much of their tour.

That doesn’t even take into consideration, Bennett added, the many reservists on both sides of the alliance – for whom the military is not a full-time role, but who fill key roles in the war plans – and the thousands of American troops, including a huge contingent of the country’s ground forces, who travel to Korea from other parts of Asia and the US and do not focus exclusively on the Korean problem set.

“Staff at all levels are put in a position to make a lot of mistakes and false assumptions because they’ve just never been put in these situations before,” Bennett said. “This can have a very dangerous impact on real-world operations.”

As Kim Joong-ro explained, exercises help establish baselines for conduct and procedure, ideally minimising internal confusion when war plans are thrown out the window upon the commencement of hostilities.

“Even if we run the exercises, we would still face many unexpected situations in real combat,” he said. “What is the point of having US forces stationed in the South if we are not running the drills together?”

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Experts on both sides of the alliance have echoed this concern. In Bennett’s view, the effects of suspending the exercise on job expertise and cross-alliance relationships that threaten readiness might, in turn, threaten the alliance’s credibility.

“[Kim Jong-un’s] ultimate objective is to get the US off the peninsula,” Bennett said. “If we suspend exercises, we have to recognise that relationships between officers become frayed, and more so over time. Undercutting alliance cohesion is a step towards this goal for North Korea.”

South Korea’s neighbour China, a long-time backer of the North Korean regime, would certainly like to see a reduction of US forces on the peninsula. Leaders in Beijing have often cited US forces there as a threat to China’s own national security, particularly after the deployment of THAAD missile defence systems in the South in 2017.

Like North Korea, China has historically opposed the allies’ large-scale drills, with the Chinese foreign ministry once describing the alliance as a relic of “cold war mentalities”.

Japan, on the other hand, views the US-South Korea alliance as a partial guarantor of its own security vis-à-vis North Korea and would likely dissent in the event of a troop drawdown.

Watch: ‘Provocative war games’: US might suspend military exercises with South Korea

Trump has questioned the utility, and expense, of basing so many US troops in South Korea. In the US, enough lawmakers bristled at Trump’s musings that the House of Representatives passed a bill in June that would limit a US president’s ability to unilaterally withdraw troops from the peninsula.

The suspension of bilateral military exercises is not entirely without precedent, though, and there are no direct indications the current halt will lead to a change in US troop disposition.

In 1992, a major spring exercise was cancelled, also amid efforts to denuclearise the peninsula. When North Korea’s then-leader Kim Il-sung blocked international inspections and ultimately reneged on commitments, the exercises promptly resumed.

In this case, too, Trump has said he may reverse his decision if Kim does not demonstrate “good faith” toward the denuclearisation they agreed upon in Singapore. It is unclear how Trump intends to quantify progress, however, after news reports that North Korea might in fact be bolstering some nuclear capabilities since their meeting.

Months of planning go into the large-scale exercises. With the autumn now certain to pass without one, the potential for their recommencement with Key Resolve in the spring is sure to be a topic of discussion when US Defence Secretary James Mattis and South Korean Defence Minister Song Young-moo meet in October, said Scott Snyder, director of the US-Korea policy programme at the Council on Foreign Relations.

Snyder and others expect the leaders may push for a continuation of exercises with their respective bosses, or at least for the reinstatement of certain exercise components without the banner public relations component that the big-name exercises traditionally entail. But there are still significant political factors at play, he said, that could jeopardise Key Resolve.

For one, South Korean President Moon Jae-in has lately pursued policies that could lead to a reduction of North and South Korean troops in the Korean demilitarised zone.

If Moon were to perceive that bilateral exercises could scuttle progress with the North Korean regime, he could advocate for a continued suspension of exercises through the Key Resolve season. On the US side, Snyder said, it was difficult to say if Trump would listen to advisers in his administration or act based on his own in-the-moment instincts.

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Whatever the case, a speedy resumption of major exercises will be needed if the alliance hopes to avoid exponential losses in readiness, said Cha Du-hyeogn, a scholar with the Asan Institute for Policy Studies in Seoul who has helped shape South Korean defence policy for decades.

As it is, Cha noted, many of those involved in planning Key Resolve on the US side will now be service members who have not themselves participated in a large-scale exercise.

Significant institutional memory exists on both sides of the alliance to guard against debilitating effects in the near term, he said, but that memory will stretch thin as further exercise windows close.

“It is a myth to say there are no impacts to readiness but hasty to draw conclusions as of now,” Cha said. “I would be seriously worried, though, if this continues in the next year, as it would significantly compromise the deterrence capability of the alliance.”