US Secretary of State Mike Pompeo intended to meet his South Korean counterpart Kang Kyung-wha on 7 October. But the visit was cancelled after US President Donald Trump contracted Covid-19.

He was expected to discuss prospects of South Korea deepening its engagement with the Quadrilateral Security Dialogue, or the Quad, consisting of the United States, India, Japan and Australia.

In recent years talk hasemergedof transforming the Quad into a veritable Asian NATO positioned to promote a free and open IndoPacific against Chinas rise. Such a development would be a marked contrast with the USs traditional hub-and-spokes style of alliances in the IndoPacific.

Awarethat Pompeo would raise the issue of the South Koreas participation in a Quad-plus format, Kangdismissed the idea of the country formally acceding to the Quad. Kang candidly stated that Seoul had no interest in participating in a US-led structural alliance in the IndoPacific.

Even in the ostensibly unlikely event that South Korea joins the Quad, such a development may ultimately be detrimental to the USs North Korea policy. US attempts to entice South Korea into the Quad for the sake of containing China could harden Beijings views of the Korean Peninsula as an area critical to its attempts to ward off Washingtons geopolitical encroachment. Pushing South Korea to join the Quad could frustrate inter-Korean reconciliation by making Beijing more inclined to support a divided Korean Peninsula, reinforcing North Korea as a buffer state.

Policy discourse in South Korea has increasingly emphasised its dual position of having a primarily pro-US security orientation while being firmly connected to the Chinese economic sphere. Seoul haspursued a strategy of avoiding conflictwith China by limiting its participation in Washingtons free and open Indo-Pacific the Quad being an integral part of US policy.

As Seoul feelsincreasing pressureto join the United States in a full-fledged anti-China alliance posture, Kangs downplaying of any real chance South Korea would join the Quad no doubt comes in part from countervailing pressure Beijing has placed on South Korea.

Yang Jiechi, a member of the Political Bureau of the Communist Party of Chinas Central Committee, visited South Koreas Director of the National Security Suh Hoon on 22 August. Yang statedthat South Korea should not stand on the US side andinsistedthat peaceful relations between China and the United States were essential for security in Northeast Asia.

For China, North Korea hasa dual meaningfor stability on the Korean Peninsula. It is critical for Chinese security on a peripheral level, while factoring heavily into Beijings power relations with Washington. South Korean accession to the Quad would only amplify North Koreas geopolitical value for China.

At present, Chinamay be willing to accept Korean unification under a South Korean government not fully aligned with the US, showing that Beijing is not inextricably wedded to the existence of North Korea as an independent state. Whereas the ROKUS alliance is primarily ensconced in deterring North Korea, absorbing the southern half of the Korean Peninsula into an explicitly anti-China network would conceivably harden Beijings position on peaceful Korean unification.

South Korea is a democracy with values and interests that largely align with the US, like all other Quad members. South Koreas comparatively more vulnerable position in relation to China, and both countries stake on the question of North Korean security means that excessive attempts to rope Seoul into an Asian NATO may backfire against US interests.

Theofficial US policy position is that it supports peaceful Korean unification in such a way that the Korean people themselves are the ultimate deciders of their fate. In taking steps that may inhibit peaceful unification, Washington may lose even more of its waning trust with Seoul if it seeks to use the Korean Peninsula as a means to contain China. As China engages in increased diplomatic outreach to South Korea, the US can ill-afford to give Seoul further doubts about its true intentions.

Washington should therefore restrain itself from pushing Seoul too hard to join the Quad as a full member, leveraging instead its shared interests with Seoul to focus foremost on seeing through an equitable solution to the Korean security crisis. South Koreas accession to the Quad will complicate Beijings ties with Seoul and entrench the Korean Peninsula as an even more explicit geopolitical battleground between China and the United States.

This article was first published in East Asia Forum.

Anthony V Rinna is a senior editor and specialist on Russian foreign policy in East Asia for the Sino-NK research group.