President Moon Jae-in and President Donald Trump had a telephone call during the evening of Sept. 4, 2017, to discuss U.S.-South Korea joint responses to Pyongyang after its sixth nuclear test. The call was two days after the recalcitrant regime claimed it had successfully completed the hydrostatic test for its intercontinental ballistic rocket installation. It is likely the phone call will draw a temporary veil over the conflict between the two allies, a conflict that was uncovered during the series of nuclear tests conducted by the rogue regime. As a calm comes after the storm, it will also hopefully allay concerns over an alleged crack in the U.S.-South Korea alliance and advance cooperation between the two countries.

However, it is too early to assume that the bone of contention between the two allies has been completely removed with one phone call. Although Seoul says Mr. Moon has consistently maintained his position that there are no resolutions to North Korea beyond sanctions and pressure, and that he has never put emphasis on dialogue alone, the South’s two allies, the U.S. and Japan, still have doubts about his platform. A day before he called his counterpart in Seoul, Mr. Trump said in a tweet, “South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work,” and this comment is most likely an oblique reference to his discomfort with the Moon administration’s heavy focus on dialogue. Presumably for a similar reason, Mr. Trump discussed the North and exchanged ideas with Prime Minister Shinzo Abe in two phone calls after Pyongyang’s latest nuclear test, prior to talking to Mr. Moon, and he has also refrained from appointing the next U.S. ambassador to South Korea for eight months. Mr. Trump’s moves even allow an interpretation that his statement on the potential termination of the U.S. trade agreement with South Korea indicates his dissatisfaction with the Moon administration.

Many years of experience have already made it clear that it is only an illusion to believe that the North would voluntarily give up its nuclear program. This delusion allowed Pyongyang to ramp up its provocations by developing an intercontinental ballistic missile and further advancing its nuclear program. To keep peace in the Korean peninsula, there is no other way than to commit to the unshakable U.S.-South Korea alliance and jointly respond to North Korea’s nuclear threats. The North Korea problem is not something that can be resolved with one call or a word. Seoul should send a clear signal to Washington that they are on the same page and act accordingly, since this is the only way to ease concerns over the so-called “Korea passing” – the idea that the U.S. and China would make a deal on North Korea without consulting the South – and to dispel South Koreans’ fears of war.