A very public back and forth between South Korea and China over the deployment of an American missile defense system erupted this week, sowing the seeds for another dramatic fallout between Seoul and Beijing.

On Wednesday, Chinese foreign ministry spokesperson Zhao Lijian urged South Korea to stick to the previous government’s promise in 2017 not to deploy any more U.S. Terminal High Altitude Area Defense (THAAD) missile interceptor systems. At the time, Beijing complained that THAAD’s radar system could be used to track the movement of China’s missile forces, even though the deployment came in response to North Korean missile threats.

Zhao was responding to South Korean foreign minister Park Jin, who asserted earlier this week that the so-called three nos deal reached in 2017 — no more THAAD batteries, no participation in a U.S. missile defense network and no ROK-U.S.-Japan trilateral military alliance — was not a formal agreement between Seoul and Beijing.

SHRIMP BETWEEN WHALES

The situation encapsulates South Korea’s dilemma as a “shrimp between whales.” As the old adage suggests, when China and the U.S. fight, it’s South Korea that gets caught in the middle.

Beijing may well view the THAAD deployment as demonstrating “the U.S.’s malicious intention to deliberately undermine China’s strategic security.” But Zhao likely raised eyebrows in Seoul when he said China’s opposition to the deployment “does not target the ROK.”

Chinese protests over THAAD are concerning precisely because they have targeted South Korea. Its economic boycott in response to the initial deployment in 2017 caused billions of dollars in damage to South Korea’s economy.

A few months later, after the Moon Jae-in administration took power from the conservatives, Seoul managed to convince Beijing to end the boycott by agreeing to the three nos.

The worry is that China could hit the ROK economy with another upper-cut if the Yoon Suk-yeol administration refuses to abide by his predecessor’s pledge — especially since Zhao made clear that “a commitment made should be a commitment kept despite the change of government.”

Yoon has few options but to bolster missile defense and the U.S.-ROK alliance | Image: Office of the 20th President (July 5, 2022)

However, Yoon has few options but to bolster missile defense and the U.S.-ROK alliance, considering the rapidly evolving threat from North Korea.

U.S.-DPRK and inter-Korean talks have been on ice for years now, and Kim Jong Un appears bent on developing more advanced weapons, including tactical nuclear missiles, that could be used to target the South.

From the Yoon administration’s perspective, China should focus less on demanding South Korea stick to the three nos and more on playing a “constructive role” in getting the North to denuclearize. After all, it’s North Korea that prompts South Korea and the U.S. to respond with systems like THAAD in the first place.

It doesn’t look like there’s much chance of Seoul and Beijing seeing eye to eye on this, though. While Yoon wants to join the U.S. in pressuring Pyongyang through sanctions, China is opposing new measures at the U.N., insisting that resolving problems on the peninsula requires “abandoning the old approach of imposing sanctions and exerting pressure.”

LOOKING TOUGH

Despite the Yoon administration’s stance that it won’t be bound by the three nos, it’s important to note that Seoul hasn’t yet made any moves to deploy more THAAD batteries.

While Yoon said Moon’s dealings with China undermined South Korean security during the presidential election, his transition team didn’t mention additional THAAD deployments as one of the new government’s 110 “state affairs tasks,” nor did the administration specifically mention it in its recent 120 key policy tasks.

This might mean that the Yoon government’s opposition to the three nos is political rhetoric. During the campaign, Yoon sought to contrast himself with his predecessor Moon, who he accused of being soft on China and North Korea, while portraying himself as much more pro-American.

In other words, the Yoon administration might be saying that while it won’t be bound by the three nos, that doesn’t necessarily mean it will break them. In this way, Yoon can look tough to the U.S. and his conservative political base, while not actually doing anything that would prompt retaliation from Beijing.

Neither side will make any decisions on the THAAD issue lightly | Image: U.S. Department of Defense Missile Defense Agency (Aug. 30, 2019)

There also isn’t a consensus on whether Seoul needs additional THAAD batteries.

According to a recent U.S. Congressional Research Service report, the DPRK’s recent progress in missile development suggests it’s trying to figure out ways to get around existing defense systems, including THAAD. Others argue it’s more likely that North Korea would use lower-angle, short-range missiles to strike the South, which other parts of its layered missile defense system are meant to protect against.

On top of this, South Korean defense minister Lee Jong-sup has said he would compare the cost-effectiveness of THAAD with the indigenous L-SAM II system. If Beijing really views additional THAAD deployment in the context of China-U.S. rivalry, as opposed to South Korean defenses against North Korea, the L-SAM II might be a less antagonistic alternative to the American interceptor system.

At the end of the day, a collapse of trade relations doesn’t benefit either side. China does have a lot of leverage as South Korea’s largest trading partner, but economic retaliation would harm Chinese business interests on the peninsula, too.

Even though Zhao made clear China’s position on more THAAD batteries, he didn’t directly mention economic countermeasures, meaning that Beijing isn’t restricting itself to any particular course of action.

Whatever happens, neither side will make any decisions on this contentious issue lightly.

Edited by Bryan Betts