The Biden administration is working quickly to make good on its rhetoric about making America’s alliance relationships great again. East Asia has been the primary theater for alliance repair work thus far. The new administration moved quickly to reach military cost-sharing agreements with South Korea and Japan, smoothing over a prominent source of friction left by the Trump administration.

Biden has made it clear that he wants the United States and its allies to move together when solving common problems, but this ideal is starting to run up against an inconvenient truth of divergent priorities in friendly capitals.

It may be impossible for Washington to keep both Seoul and Tokyo happy because each capital has very different ideas about what it wants out of U.S. policy toward North Korea. While both South Korea and Japan would prefer to see North Korea completely denuclearize, the two U.S. allies have different priorities and their approaches to the problem vary significantly.

Generally speaking, the Moon Jae-in administration in Seoul would like to do more to incentivize North Korea to improve relations with both South Korea and the United States. Getting rid of North Korea’s nuclear weapons is one of the major goals of South Korea’s strategy, but achieving denuclearization will require improvements in other policy areas along the way. South Korea’s efforts to reduce the risk of conventional military actions along the DMZ, plans for greater economic engagement and infrastructure improvements, and calls for a peace declaration to end the Korean War are examples of how Seoul prioritizes broader engagement efforts as a way to eventually achieve denuclearization. This approach enjoyed some early success in 2018, but after the failure of the U.S.-North Korea summit in Hanoi in February 2019, the North has effectively shut down the South’s engagement push.

Compared to South Korea’s approach, Japan’s position contains very little room for engagement with North Korea until it makes significant steps toward denuclearization. While South Korea and the United States engaged in summit diplomacy with Kim Jong Un in 2018, Tokyo reiterated that sanctions on North Korea should not be lifted until it gives up nuclear weapons. Engagement is not completely off the table. Former prime minister Shinzo Abe, for example, said that he would be willing to negotiate directly with Kim Jong Un without preconditions. This offer of a summit was the exception to the rule, however, and Japan’s approach to North Korea’s nuclear program has generally favored greater pressure over engagement.

This presents a frustrating choice for the Biden administration if it remains committed to working closely with allies to address North Korea’s nuclear program. Adopting policies that favor Seoul’s approach of greater engagement with North Korea and place denuclearization as one of many goals for diplomacy would necessarily place the United States at odds with Japan’s preferences for denuclearization first. Hewing closely to Tokyo’s approach would mean throttling back on the engagement efforts that South Korea favors.

Early signs suggest the Biden administration will favor Japan over South Korea in this dilemma. In a statement released after the first leader-level Quad summit on March 12, the United States backed away from the phrase “denuclearization of the Korean Peninsula” and instead committed to the “denuclearization of North Korea.” The former phrase was an important feature of both the April 2018 Panmunjom Declaration for Peace and the June 2018 Singapore summit joint statement, which South Korea participated in and strongly supported, respectively. The State Department repeated the “denuclearization of North Korea” formula in a March 14 press release that previewed an upcoming visit to Japan by the U.S. secretaries of state and defense.

Washington’s review of its North Korea policy is still ongoing but based on these recent statements it seems likely that the Biden administration will adopt a policy that is more closely aligned with Japan’s rather than South Korea’s preferences. This would be bad news for the Moon administration, which has consistently stressed the need for greater U.S. engagement with North Korea despite Kim going to ground after the Hanoi summit.

A tougher U.S. policy that brings Washington and Tokyo into closer alignment would help Biden differentiate himself from Trump, but it is unlikely to nudge North Korea closer to either denuclearization or arms control. Instead of trying to make allies happy, the Biden administration should focus on looking out for the best interests of the United States.