North Korea’s leader Kim Jong-un, bursting with confidence from his alliance with the Russians in Ukraine, is now urging a great leap forward in his nuclear program.

More than seven years after ordering the North’s sixth nuclear test, Mr. Kim appears eager to stage a seventh, despite the opposition of the People’s Republic of China. This time, it’s believed, such a test would be even more powerful than the last blast that blew up much of a mountain in September 2017.

“We fear this might be the time when the DPRK (Democratic People’s Republic of Korea) starts the  fire on the seventh nuclear test,” said a senior researcher with the Korea Institute for Defense Analyses, Lee Soo-hoon. “The explosive yield will be a lot more than the sixth nuclear test,” he told a forum at the Center for Strategic and International Studies in Washington.

Anxiety about Mr. Kim’s nuclear program has risen as North Korean forces join the Russians in Ukraine, getting their first taste of combat — and training for a wider war not only in Ukraine but possibly Korea, too.  “We will build up our nation’s self-defense forces, the pivot of which is its nuclear capability, limitlessly and endlessly,” Mr. Kim told a meeting of battalion commanders and political officers, as reported by Pyongyang’s Korean Central News Agency.

“Long ago, the line of building up our nuclear forces became an irreversible policy,” KCNA quoted him as saying in a speech translated into English. “What remains to be done now is for these forces to get more fully ready for action.”

While Mr. Kim’s rhetoric may be dismissed as bluff and bluster, he appears to have become obsessed with the war in Ukraine — so much so as to give the impression that he’s now far more certain than in bygone years of his ability to get away with a sharp escalation in tensions if not actual war in Korea.

Without mentioning his decision to send 12,000 troops to fight for the hard-pressed Russians, Mr. Kim accused “the United States and other Western countries” of “using Ukraine as a shock force in the war against Russia.” He neglected to note that no forces from the North Atlantic Treaty countries are in Ukraine when he said their goal was “to enrich their real-war experience and expand the scope of military intervention all over the world.”

It’s  the North Koreans who are gaining in Ukraine combat experience that they will bring back with them to North Korea. Voice of America quoted Ukraine’s ambassador to South Korea, Dmytro Ponomarenko, as saying the North Koreans may be rotated in and out every few months, meaning as many as 100,000 might gain experience on the battlefields of Ukraine within a year.