President Trump is facing what may be an insurmountable obstacle to a fourth meeting with the North Korean leader: Kim Jong-un’s renewed vow to expand his nuclear program.

On the 77th anniversary of the founding of North Korea’s armed forces, Pyongyang’s Korean Central News Agency said Mr. Kim “clarified once again the unshakable policy of more highly developing the nuclear forces” in accordance with “new plans for rapidly bolstering all deterrents.”

This was after Mr. Trump, from Washington, said flatly, “We will have relations with North Korea, with Kim Jong-un.” When Mr. Kim left no doubt of his ambition to build more warheads, and the missiles to send them to distant targets, his remarks appeared almost like a direct rebuff of Mr. Trump, who has repeatedly said he hopes the two can meet again. 

Sitting beside Prime Minister Ishiba of Japan in the Oval Office on Friday, Mr. Trump recalled the personal relationship he believed he had formed with Mr. Kim, with whom he has often said he “fell in love” during their first summit, in Singapore in June 2018.  He seemed to think the relationship had blossomed in their two subsequent meetings — a summit at Hanoi in February 2019 and a third meeting four months later at Panmunjom on the line between the two Koreas.

Mr. Trump did not, however, mention the basic reason for Mr. Kim to avoid welcoming a reunion — the humiliation of Mr. Trump’s abrupt walkout from their Hanoi summit after Mr. Kim refused to give up his nuclear program.

So angered was Mr. Kim that he ordered the execution of his nuclear envoy to Washington and other officials whom he believed had deliberately misled him into believing Mr. Trump would recognize the North as a nuclear power, according to South Korea’s biggest-selling newspaper, Chosun Ilbo.

Skipping the debacle in Hanoi, Mr. Trump said he “had a good relationship” with Mr. Kim, and “I think it’s a very big asset for everybody that I do get along with them” — meaning not only Mr. Kim but others in his entourage.

Mr. Kim did not refer to Mr. Trump or their previous meetings as he launched into hyperbolic language, describing his nuclear forces as “immutable ones for real war to promptly smash the origin of any attempt of the hostile forces to infringe the sovereignty of the country and the security of its people and threaten regional peace.”

Without alluding to either America or Japan, Mr. Kim’s remarks appeared to reflect his fury over the affirmation, in the joint statement issued by Messrs. Trump and Ishiba, of longstanding demands for North Korea’s “complete denuclearization.” The inference was that Mr. Trump had never budged from his position in Hanoi that the North had to give up its nukes — and the missiles to send them to distant targets, including America and Japan as well as South Korea — as a condition for a real deal with Washington.

Also, Mr. Kim of course could not have been happy about the statement’s declaration of “the need to deter and counter” North Korea’s “malicious cyber activities” and its “increasing military cooperation with Russia.” It was the allusion to the North’s role in the Ukraine war that presumably prompted him to come close to acknowledging for the first time that he’s ordered North Korean forces to fight for the Russians.

Both Mr. Kim and President Putin have chosen not to mention the presence of the North Koreans, who wear Russian uniforms and carry phony Russian ID cards.

“Our army and people will invariably support and encourage the just cause of the Russian army and people to defend their sovereignty, security and territorial integrity,” KCNA quoted Mr. Kim as saying. That was said to be “in keeping with the spirit of the treaty on the comprehensive strategic partnership” between the North and Russia reached in the mutual defense treaty signed during Mr. Putin’s visit to Pyongyang last June.