ANALYSIS — President Donald Trump once claimed he and North Korean leader Kim Jong Un “fell in love.” But the dictator he once called “Little Rocket Man” let him know on Friday that their “mysteriously wonderful” relationship might not be enough to strike a disarmament pact.

As recently as Wednesday, the U.S. commander in chief signaled he continues to believe the unlikely warm relationship with Kim could drive a deal under which Kim would give up his nuclear arms.

“[We] seem to have a very good relationship,” Trump told reporters when asked for an update on negotiations in the wake of a summit with Kim last month that collapsed over differences about removing sanctions before the North has proven it is dismantling its program and the definition of what would constitute “denuclearization.”

North Korea’s vice foreign minister, Choe Son-hui, told reporters in Pyongyang the same, saying Friday the two leaders’ relations are “still good, and the chemistry is mysteriously wonderful,” according to The Associated Press, which has a bureau in the North’s capital city.

But Choe blamed Secretary of State Mike Pompeo and White House national security adviser John Bolton for fostering an “atmosphere of hostility and mistrust” in Hanoi, Vietnam, adding they were too fixed in their demands and “were too busy with pursuing their own political interests and had no sincere intention to achieve a result.”

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Here are three things to watch from Kim and Trump as their relationship enters a new phase.

Testing tensions

Trump has repeatedly said he does not get enough credit for securing from Kim a promise to cease nuclear and missile tests, a pledge U.S. officials say the dictator has lived up to. But Choe signaled Kim is mulling a resumption of the test program.

“Whether to maintain this moratorium or not is the decision of our chairman of the state affairs commission,” she said. “He will make his decision in a short period of time.”

David Maxwell, a retired Army colonel who served in Asia for two decades, said a resumption of testing would serve Kim’s political goals as much as learning more about his weapons and improving their performance.

Kim uses his missiles tests to conduct what Maxwell, now a senior fellow at the Foundation for Defense of Democracies think tank, calls “blackmail diplomacy” to achieve “political and economic concessions” and to trigger “a response from Japan and South Korea and from the United States. It’s an important part of [Kim’s] diplomatic arsenal that is really political warfare.”

Size matters

Trump often fixates on size — from the size of his inauguration crowd to how many supporters show up at his political rallies to his “nuclear button.” But while he has lauded Kim’s testing freeze, he and his team have said very little about the North’s still-operating missile factories.

Rebeccah Heinrichs, senior fellow at Hudson Institute who once advised former Arizona GOP Rep. Trent Franks on national security issues, said Friday at an event in Washington that “Trump talks about how Kim has stopped testing as an achievement.”

“He’s partially right. But you don’t need to keep testing to get up to [a] credible threat,” Heinrichs said. “But you can improve upon the threat by increasing the number of missiles that you have.”

The bottom line, she concluded of the North’s strongman, is “there is no sign he’s stopped producing missiles.”

Proportional response?

So far, the White House and president have been mum about Choe’s threats. But how Trump chooses to respond will be telling — and could escalate tensions after he has for months predicted an eventual deal.

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Press Secretary Sarah Huckabee Sanders did not respond to an inquiry seeking comment. But on Monday she called Chinese officials’ concerns that her boss is an unreliable negotiator “absurd,” adding during what was only the second White House news briefing of the year that “the president is going to make a deal if it’s a good deal — he’s going to make a deal if it’s in the best interest of America.”

But Trump often employs scorched-earth messaging. That goes for foes foreign and domestic. And there are reasons for the U.S. president to be frustrated and worried.

Though Kim’s missiles always have taken errant flight paths, Heinrichs warns Kim’s weapons “could get really close” to any intended targets in Asia or inside the continental United States.

“We should not rest soundly knowing the North Koreans haven’t proven this capability through a test,” she said Friday. At the same event, Maxwell noted that if hostilities broke out in the region, Kim’s missiles likely are accurate enough to take out key targets like sea ports in South Korea and United Nations bases in Japan that would be used to “flow U.S. forces … into war.”

The North’s missile arsenal “is really one of the treasured swords that Kim Jong Un yields to advance his interests,” he said.

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