South Korea hits back against Putin-Xi defense pact

South Korea is reacting sharply today to a Treaty on Comprehensive Strategic Partnership signed Wednesday by Russian President Vladimir Putin and North Korea’s Supreme Leader Kim Jong Un.

The treaty notably included a mutual defense clause invoking a defense pact: in the “case any one of the two sides is put in a state of war by an armed invasion from an individual state or several states, the other side shall provide military and other assistance with all means in its possession without delay in accordance with Article 51 of the UN Charter and the laws of the DPRK and the Russian Federation.”

The future implications of such an agreement remain uncertain, but the underlying motivation for its signing can be gleaned from Putin’s press statements in Pyongyang. The Russian leader drew attention to the U.S. and NATO supplying to Ukraine “long-range high-precision weapons, F-16 aircraft and other technology-intensive arms and equipment for delivering strikes at Russian territory.”

Putin went on to state that “In this context, the Russian Federation does not rule out developing military and technical cooperation with the Democratic People’s Republic of Korea under the document signed today.”

Clearly, Moscow is demonstrating its ability and willingness to undermine Washington’s policy on the Korean Peninsula — a policy that, in principle, Russia had previously backed by endorsing UN sanctions against North Korea. While Putin has been cautious in not seeking an expansion of the fighting in Ukraine to neighboring NATO member-states, in response to US military aid to Ukraine he has expanded ties with Washington’s adversaries and sought to disrupt long-standing American policies from East Asia to the Middle East and beyond.

In response to the treaty, South Korea stated that it will “reconsider the issue of arms support to Ukraine.” At Washington’s request, Seoul has already indirectly sent hundreds of thousands of artillery shells to Ukraine. In fact, South Korea in 2023 indirectly sent more 155mm artillery shells to Ukraine than all European countries combined. This has played an important part in helping Ukraine, which is suffering from serious shortages of ammunition. However, Seoul has so far refrained from dispatching weapons — as opposed to ammunition — to Kyiv to avoid antagonizing Russia.

On the one hand, the revitalized Russia-North Korea defense ties could prompt Seoul to revisit its relatively accommodative policy toward Moscow. On the other, the Kremlin presumably hopes that increased tension on the Korean peninsula will discourage Seoul from drawing down its own stocks of ammunition to supply Ukraine, and will remind Washington of the damage that Russia can do to U.S. interests around the world if it increases its own aid to Ukraine and abandons restrictions on how far Ukraine can use U.S. weapons to attack Russian territory.

Prior to the Putin-Kim summit, South Korean officials had warned Moscow “not to go beyond a certain point” in its defense cooperation with Pyongyang and vowed to take necessary countermeasures depending on the summit’s outcomes. Reiterating his government’s desire to maintain stable ties with Russia, South Korean National Security Advisor Chang Ho-jin stated in a recent interview, “Moscow should take into consideration which among North Korea and South Korea will be more important to it, once Russia ends its war with Ukraine.”

From Seoul’s perspective, Russia’s seemingly unambiguous commitment to supporting Pyongyang in a potential Korean Peninsula conflict — as suggested in their new mutual defense pact — can be viewed as an indication that Moscow is shifting its policy toward the Korean peninsula from pursuing cooperative relations with both Koreas to not minding an adversarial relationship with South Korea for the sake of cooperation with North Korea.

It has been widely reported – although both Pyongyang and Moscow deny it – that North Korea has supplied Russia with millions of shells and scores of ballistic missiles for its war in Ukraine. The impression that Moscow is more clearly siding with Pyongyang will certainly motivate Seoul to rethink its so-far restrained position on the issue of arms supplies to Ukraine.

With the idea of accommodating Moscow to disincentivize its military cooperation with Pyongyang increasingly proving to be a false hope, Seoul may no longer find a strong incentive to bear the political burden of refusing its crucial ally Washington’s calls for South Korean military aid to Ukraine. As the battlefield situation in Ukraine shifts in favor of Russia, U.S. pressure on South Korea to send munitions and weapons to Ukraine would only grow, making it more difficult for Seoul to keep resisting cooperation on that front.

Seoul is also likely provoked by Moscow’s seeming disregard for its several warnings not to cross the line and therefore could find it necessary to respond with strong retaliation in demonstration of resolve. The sense of bitterness could reinforce voices in Seoul calling for sending weapons to Ukraine and weaken voices calling for continued restraint.

Additionally, South Korean President Yoon Suk-yeol’s continuous struggle to boost his approval rating, which has been hovering around the low 20s, can serve as another motivation for Seoul to consider arms supplies to Ukraine. Showing defiance of Moscow would appeal to the ruling party’s traditionally anti-communist conservative political support base and may also gain support from the broader population who might feel embittered by what they would see as Moscow’s betrayal of their country’s prudent restraint.

To be sure, there are also factors that may compel Seoul to think twice about supplying military aid to Ukraine. Exporting a chunk of its stockpiles to Ukraine comes with a dilemma that South Korea’s own readiness against North Korea would be reduced.

Another question Seoul must consider is what Moscow’s reaction would be if it did send Ukraine sophisticated weaponry. Speaking in Vietnam on Thursday, Putin said South Korea had “nothing to worry about” but cautioned against sending arms to Ukraine as “that would be a very big mistake.” The Putin-Kim joint statement’s relatively vague language on defense capabilities cooperation may leave space for Moscow to refrain from providing Pyongyang with military technologies that Seoul would consider a “red line,” including advanced missile and nuclear development technologies.

However, if Seoul does increase its arms supplies to Ukraine, the result may well be to bring about Pyongyang’s possession of more advanced ballistic missile and tactical nuclear capabilities with Moscow’s assistance — something that is regarded in South Korea as a nightmare scenario.

It is also questionable how much South Korean arms can improve Ukraine’s position on the battlefield. From Moscow’s view, the military, economic, and demographic fundamentals of the battlefield strongly favor Russia's ability to effectively continue waging war against Ukraine. The provision of increased lethal aid from South Korea may or may not alter these fundamentals.

However, previous examples demonstrate that there has yet to be any silver bullet weapon that dramatically alters Ukraine’s ability to dislodge the Russian armed forces from significant portions of occupied Ukrainian territory. Seoul may worry about the risk that its munitions might only serve to further provoke Moscow and encourage more dangerous Russian military cooperation with North Korea without meaningfully improving Ukraine’s battlefield situation.

Whether Seoul decides to step up as an arms supplier for Ukraine remains to be seen, but overall, the possibility seems to have certainly increased in light of the upgraded Russia-North Korea defense pact.

As the threat of new wars proliferate from Europe to the Middle East, and potential conflicts simmer in East Asia, the lack of active and serious communication channels between Washington and Moscow produces ripe environments for an uncontrolled security spiral between the two nuclear superpowers.

As long as Russia believes that the U.S. is continuing to tighten the screws around it in Ukraine (or elsewhere in its “near abroad”), Moscow will play its cards to undermine and create problems for the U.S. and its allies across the globe. The dangers of this continuing unchecked could lead to severe consequences for many more than just those already suffering in Ukraine or on either side of the 38th parallel.