President Trump is planning to tell President Zelensky on Friday that President Putin will stick to whatever deal he makes on Ukraine, even as fresh North Korean troops are joining Russia’s war.

 “If we make a deal, it’s gonna hold,” Mr. Trump told Prime Minister Starmer in the Oval Office before they sat down for their summit. To which he added that he and Mr. Zelensky were “going to sign a deal.” 

Mr. Trump was referring specifically to an agreement not on ending the war but on Ukraine giving Washington access to critical rare earth minerals badly needed for computers and other gizmos as payment for more than $300 billion in arms provided to Ukraine over the past three years since the Russian invasion. 

Neither he nor Mr. Starmer spoke of the role of North Korean troops, who’ve suffered heavy casualties since the first wave of about 12,000 arrived last month as the North’s leader, Kim Jong-un, makes good on promises to Mr. Putin, with whom he signed a new treaty in June. 

North Korean troops “were placed back in the frontline” of the Kursk region of Russia, bordering  eastern Ukraine, according to South Korea’s National Intelligence Service, formerly known as the Korean Central Intelligence Agency. 

The NIS, normally taciturn if not totally silent, let the South Korean press know about the deployment while Mr. Trump lays the groundwork for “the framework” for ending the war in two critical White House meetings. He began Thursday with Mr. Starmer, who advocates a tough line but repeatedly emphasized the close Anglo-American bond. The president faces a more severe challenge Friday with Mr. Zelensky.

“It appears that there has been a deployment of additional troops, but their size is still being examined,” the NIS said. South Korea’s Yonhap News said military officials estimated that about a thousand North Koreans had been sent to Russia to replace North Koreans killed earlier in their first round of fighting. The troops reportedly were transported via “Russian cargo ships and military airplanes between January and February in the second round of such troop deployment.”

A South Korean website that covers North Korea, NK News, reported that the chief of intelligence for Ukraine, Krylo Budanov,  estimates North Korea now is providing half the arms that Russia needs for its front line troops while Russia increases production of drones and “guided aerial bombs.”

Mr. Budanov, in a press conference at Kviv, said North Korea had also provided 170-mm self-propelled guns and 240-mm multiple rocket systems, NK News reported. North Korean instructors, he said, “help train personnel to operate this equipment.”

Mr. Zelensky, in his meeting with Mr. Trump, is sure to explain his pessimism over Mr. Putin agreeing to any deal that’s both verifiable and enforceable. The issue of North Korea’s role is likely to enter the conversation in view of Mr. Trump’s relationship with Mr. Kim, whom he first met at their Singapore summit in June 2018 and saw two more times in 2019 in a vain effort to get him to agree to give up his nuclear program.

Mr. Trump, of course, will reiterate to Mr. Zelensky what he already knows, that Ukraine is simply not going to be admitted to the North Atlantic Treaty Organization as he ardently wishes. Even if other NATO nations are open to Ukrainian membership, Mr. Trump made clear that Washington will veto the idea, which he said was to blame for Russia entering the war in the first place.

Mr. Trump is much more optimistic, though, about the chances for peace without the need for NATO’s involvement. As he said Thursday in the Oval Office with Mr. Starmer, when asked if Mr. Putin might agree to return territory seized before the outbreak of all-out war: “We’ll certainly try and get as much as we can back.” He’ll surely tell Mr. Zelensky the same.

It was clear, though, there’s no guarantee when Mr. Trump added, “We’ll be talking about getting it back if possible.

He was equally vague about a European peace-keeping force deploying to Ukraine. “We have to make a deal first,” he said. “Now we don’t have a deal. I don’t like to talk about peacekeeping until we have a deal.”

Mr. Zelensky is not likely to believe Mr. Trump, especially if he says, as he did Thursday, “I’ve known him [Mr. Putin] for a long time now … I don’t believe he’ll violate his word.”

On a personal level, though, Mr. Zelensky should find Mr. Trump reassuringly pleasant. Mr. Trump was politely vague when asked if he still believed Mr. Zelensky was a “dictator,” as he described him last weekend.

“Did I say that?” he responded almost tongue-in-cheek. “I can’t believe I said that. Next question.”