Amid speculation that the momentum of his flimsily constructed détente with Kim Jong Un is grinding to an embarrassing halt, Donald Trump posted a late-night tweet praising the North Korean dictator for sending home 55 flag-swathed caskets ostensibly holding the remains of U.S. service members lost during the Korean War. “Thank you to Chairman Kim Jong Un for keeping your word & starting the process of sending home the remains of our great and beloved missing fallen!” he wrote, perhaps in the hope that the public might interpret Kim making good on a one-line promise as a first step toward total nuclear disarmament. “I am not at all surprised that you took this kind action,” the president added, encouragingly. Vice President Mike Pence personally flew out to Joint Base Pearl Harbor-Hickam in Honolulu to greet the cases as they were unloaded from two hulking C-17 military aircraft.

Unfortunately, the celebrations may be premature, given the complexity of transferring and identifying the remains. According to Pentagon estimates, of the roughly 7,700 unaccounted for Americans lost during the Korean War, 5,300 are thought to have died in North Korean territory. Of that number, despite continued efforts, only 450 sets of remains have been returned to the U.S., and only 181 individuals have been identified. Many have turned out not to be American. Indeed, when North Korea sent 208 caskets to the U.S. between 1990 and 1994, it was discovered that they contained the jumbled remains of many more people. The contents of the 55 caskets could be similarly diverse, and those charged with sorting through them have been provided with no personal effects to help them, save a sole military dog tag.

Identifying the remains could take years. And in the end, they might not turn out to be human at all. In 2011, when North Korea sent the remains of Flight Lieutenant Desmond Hinton back to the U.K., subsequent DNA tests revealed the casket contained animal bones—a result that reportedly remained secret for fear of damaging relations with Pyongyang, until it was disclosed in the memoirs of North Korean diplomat who defected to South Korea.

None of this seems to have phased Trump, who has energetically boasted of his dealmaking prowess since returning from Singapore in June. But despite the president’s insistence that “there is no longer a Nuclear Threat from North Korea,” cracks between Trump and Kim’s interpretations of disarmament are beginning to appear. Earlier this week, several reports emerged that North Korea is continuing its work on at least one intercontinental missile and that its uranium-enrichment operations are extant as well. When prompted during a hearing before the Senate Foreign Relations Committee last week, Secretary of State Mike Pompeo confirmed that the North Koreans “continue to produce fissile material.”

Of course, there’s no reason North Korea would have ceased its nuclear-weapons operations: despite the posturing of the Trump administration, it never explicitly promised to do so, and it has invested heavily in nuclear capabilities since Kim came to power. “What this illustrates is that the Trump Administration either doesn’t understand—or isn’t being honest about—what North Korea wants,” nonproliferation expert Jeffrey Lewis recently told my colleague Abigail Tracy. “North Korea is looking for the same deal Israel has—they get to keep the bomb as long as they don’t make too much of a fuss about it.” It’s perhaps with this end goal in mind that Kim found it in his heart to send back the remains of U.S. soldiers, counting on the gesture to extend the timeline of his shambling negotiations with the United States, and to head off any Twitter histrionics from the president.