On June 19, Russian President Vladimir Putin landed in Pyongyang, where he received a warm welcome from North Korean leader Kim Jong Un. This visit was far from a routine diplomatic engagement; the two leaders announced a new security alliance and pledged to strengthen military cooperation.
The meeting comes as North Korea expands its military ambitions. With wars raging in Europe and the Middle East, rising tensions in the South China Sea, and the looming threat of conflict over Taiwan, it is crucial for Washington to get its deterrence strategy right on the Korean Peninsula. Although the Biden administration has taken positive steps, its current approach falls short and urgently needs enhancement to effectively counter North Korean objectives.
The Washington Declaration
Current U.S. policy toward the Korean Peninsula rests on the April 2023 Washington Declaration. When South Korean President Yoon Suk-yeol visited Washington last year, U.S. officials were concerned about North Korean aggression and Seoul’s flirtation with building an independent nuclear arsenal. At the core of both issues was a lack of credibility in U.S. extended deterrence.
The answer that the United States and South Korea developed is the Washington Declaration, which stipulates five key provisions: (1) South Korea will recommit to the nuclear non-proliferation regime, (2) Washington will commit to making every effort to consult with Seoul before using nuclear weapons on the Korean Peninsula, (3) the two countries will establish a senior-level nuclear consultative group, (4) the United States will carry out visible deployments of strategic assets, and (5) the two nations will deepen military training and exercises while integrating South Korean capabilities into U.S. strategic planning.
The results of this agreement have been mixed.
On the one hand, both sides have diligently pursued the provisions outlined in the Washington Declaration. Yoon reiterated that South Korea would adhere to the Non-Proliferation Treaty. Seoul and Washington have also held several nuclear consultative group meetings and made significant progress. They recently held the third iteration and announced advancement on new nuclear use guidelines.
Furthermore, Washington has been very intentional in pursuing the last two provisions. Last year, for the first time since the 1980s, a nuclear-armed ballistic missile submarine visited South Korea. In October, the nuclear-capable B-52 strategic bomber landed in South Korea for the first time. Moreover, South Korea-U.S. military exercises utilize more troops and new platforms accompanied by expanded scope.
In a recent interview, U.S. Deputy Secretary of State Kurt Campbell reaffirmed the administration’s commitment to their current strategy. “The Washington Declaration and the strategic initiatives that have been launched to underscore the added significance of American extended deterrence, particularly in situations like Korea, I think it’s given us what we need to work with now,” Campbell said.
However, despite both nations committing to the spirit of the Washington Declaration, it has proved insufficient.
Not Failing, But Not Succeeding
While it’s fair to say that the Washington Declaration hasn’t failed – North Korea hasn’t invaded South Korea, after all – it’s also becoming clear that it’s not succeeding either. The Washington Declaration has two goals: deter North Korean aggression and reassure South Koreans of U.S. extended deterrence. Recent trends demonstrate neither is happening.
The Washington Declaration has proven ineffective in deterring North Korea. Since U.S. President Joe Biden took office in 2021, North Korea has conducted around 115 missile tests, which is double the amount of tests performed during President Donald Trump’s administration. North Korea terminated the 2018 Comprehensive Military Agreement last year after violating it with a satellite launch, and earlier this year, Kim Jong Un announced he no longer sought reconciliation with South Korea.
Pyongyang’s more assertive approach is only going to be buoyed by its new Comprehensive Strategic Partnership Treaty with Russia, which calls for tighter security cooperation and vows to “immediately provide military and other assistance” should one of the nations be a victim of armed aggression. As North Korea’s capabilities and willpower grow, the United States and South Korea must not only match it but surpass it.
Second, the Washington Declaration has not been enough to reassure South Koreans about the credibility of U.S. extended deterrence. There is a growing demand in South Korea for Seoul to pursue its own nuclear weapons. The Asan Institute’s 2024 South Korea and Their Neighbors Report shows that South Koreans increasingly desire to develop an independent nuclear arsenal. While support for building an independent nuclear arsenal has always been high, it is getting noticeably more popular. During the Trump administration, South Korean support for developing nuclear weapons averaged around 63 percent. Since Biden took office, this support has increased to 68 percent, reaching an all-time high of 70 percent in 2024.
This trend is confirmed by the Korea Institute for National Unification’s 2024 poll, which showed 66 percent support for South Korea developing its own nuclear weapons, a six point boost from its 2023 poll. While South Korean elites generally do not support the development of nuclear weapons, there is a growing number of lawmakers and experts advocating for this approach.
Despite the United States faithfully executing the provisions in the Washington Declaration, it’s not enough. Washington has to do more to establish credible deterrence and reassurance.
Washington’s Menu of Options
The United States needs to reimagine deterrence and reassurance on the Korean Peninsula. Three viable options include a Washington Declaration 2.0, nuclear sharing, and a South Korea Relations Act.
The first obvious solution is making the Washington Declaration work by augmenting its current provisions. Put simply, it would mean doing more of everything.
Currently, the nuclear consultative group is run at the assistant secretary level, and while that is appropriate to achieve bureaucratic progress, it is inadequate for deterrence signaling. Raising the convening to the under secretary or deputy secretary level would send a stronger signal to both Pyongyang and Seoul about the seriousness of U.S. commitments.
Another critical component of this plan would be increasing the frequency at which strategic assets visit South Korea. As of now, only one nuclear-capable submarine has visited South Korea. Several nuclear-capable bombers have conducted exercises over South Korea, but a nuclear-capable bomber has only landed in the country once, in 2023. There have been no visits in 2024. If the Biden administration wants to make the Washington Declaration work, it must pursue the initiatives more vigorously.
The second option is the redeployment of U.S.-controlled tactical nuclear weapons to South Korea. This approach would likely result in further destabilization of relations in the near term, but could arguably strengthen deterrence against North Korea and reassurance with South Korea in the long term.
However, the United States suffers from a limited nuclear arsenal. The United States only has around 200 tactical nuclear weapons. One hundred are in Europe, and the other hundred are in strategic reserve in the United States. Deciding which pot to redeploy from would undoubtedly come with political and security costs.
Additionally, South Korea would face severe economic coercion from China, which would not approve of the redeployment. Beijing slapped economic penalties on South Korea in 2016 when Washington established a missile defense system on South Korean soil; their reaction to the return of nuclear weapons to South Korea will surely garner a more brutal response.
If the administration won’t consider the above options, then the White House should pursue more substantial political signaling by working with Congress to pass a law akin to the Taiwan Relations Act. In the 1970s, when the United States officially ended relations with Taiwan, Congress passed the Taiwan Relations Act to show ongoing U.S. support for Taiwan. This act confirmed the United States’ strong commitment to peace in the Taiwan Strait.
A South Korea Relations Act should take a similar tactic. In the strongest terms, Congress should reaffirm the United States’ security treaty with South Korea and stipulate that any attack on South Korea would be met with an immediate and forceful military response. While a South Korea Relations Act wouldn’t actually change much of existing U.S. policy, it would demonstrate a united front against North Korea and help reassure Seoul of Washington’s commitment to its security.
Conclusion
While the Biden administration has made commendable efforts through the Washington Declaration to enhance deterrence and reassure South Korea, these measures are falling short in the face of North Korea’s escalating aggression and South Korea’s waning trust in U.S. security commitments. The increasing missile tests by North Korea and the growing public support in South Korea for an independent nuclear arsenal highlight the inadequacy of the current strategy.
To address these challenges, the United States must consider a more robust approach, whether through an augmented Washington Declaration, redeployment of tactical nuclear weapons, or a legislative commitment akin to the Taiwan Relations Act. Only by reinforcing its deterrence and reassurance mechanisms can Washington effectively manage the evolving security dynamics on the Korean Peninsula.