North and South Korea are on the brink of going to war with one another, but on the battlefields of Ukraine rather than the Korean peninsula. 

North Korea is already sending military “advisers” to Ukraine along with hundreds of thousands of artillery shells and other munitions, while South Korea is eager to retaliate by shipping arms and artillery shells directly to Ukraine rather than through third countries such as Poland.

No, South Korea won’t be ordering soldiers to face the North Koreans — at least not yet — but the prospect of the South, one of the world’s top 10 arms manufacturers, making its debut as a major direct contributor of much-needed weaponry for Ukraine’s embattled forces adds a new dimension to the war.

South Korea first hinted at a drastic response to North Korea sending troops to Ukraine when the South’s vice foreign minister, Kim Hong-kyun, advised the Russian ambassador to South Korea, Georgy Zinoviev, “in the strongest terms” of the consequences of the North’s “illegal military cooperation” with the Russians in Ukraine.

The South’s National Security Council is now making clear that warning was no pro forma diplomatic protest. Criticizing the dispatch of North Korean troops to Ukraine as “a significant security threat” in “blatant violation” of UN Security Council sanctions, the council has decided on “phased measures” to show it’s not engaging in empty rhetoric.

South Korea’s Yonhap news quotes the deputy national security adviser, Kim Tae-hyo, as warning, “If the illegal military cooperation between North Korea and Russia continues, [South Korea] will not stand by but respond firmly in collaboration with the international community.”

It was left to a “senior presidential official” to make clear that “phased measures” enhancing South Korea’s role in the war would “include sending defensive and offensive weapons,” Yonhap reported.

South Korea has responded with alarm to news of the first shipment of 1,200 North Korean military advisers to Ukraine aboard Russian vessels — the vanguard of 12,000 that the South’s National Intelligence Service says will be dispatched to assist hard-pressed Russian forces.

North Korea’s direct participation in the war climaxes steady progress in Pyongyang’s relations with Moscow that began with leader Kim Jong-un meeting President Putin in September of last year at the Vostochny Cosmodrome near the Amur River in Siberia, during which Mr. Kim agreed to provide Russia with much needed-artillery shells. Messrs. Putin and Kim also met last June at Pyongyang, where they signed an enhanced agreement on mutual defense.

North Korea, even as it destroys road and rail links with the South on its side of the demarcation line, has said nothing about sending troops to Ukraine, but Yonhap reports a “pro-Russia Telegram account” posted “a  photo showing the Russian and North Korean flags side by side on a Ukrainian battlefield.”

South Korean officials are not worried about the costs of weaponizing Ukrainian forces. For the South’s burgeoning defense industry, a new market in Ukraine promises a fresh bonanza of exports.

“As South Korea continues to secure massive, back-to-back defense deals, the country has emerged as a force in the global defense industry,” a report issued by the Stimson Center at Washington says. “South Korean President Yoon Suk-yeol has made expanding the defense industry a core tenet of his presidency, promoting several policies in service of his goal to make South Korea the world’s fourth-largest defense exporter by 2027.”

The report from two young researchers, Hunter Slingbaum and  Kaitlyn King, notes that the South’s defense buildup “has focused primarily on arms exports of vehicles such as combat aircraft and tanks and artillery, as well as the shipbuilding industry,” all much needed for Ukraine’s depleted military establishment. 

North Korean troops joining in the war in Ukraine has grave implications on the ground in Korea. 

“We must actively utilize the logic of responding to the nuclear threat alliance between North Korea and Russia,” a visiting fellow at the Asan Institute in Seoul, Cha Du Hyeon, writes. Now, he says, Washington and Seoul must consider “the redeployment of tactical nuclear weapons to the Korean Peninsula and the strengthening of South Korea’s own nuclear capabilities” — a crucial step in escalation that Washington would like to avoid.