And the stakes keep rising.
One day after Trump fired off a blistering and improvised warning to rain "fire and fury" over the communist state if it kept up its own threats, North Korea issued an unusually specific and provocative warning, threatening to send four missiles toward Guam while ridiculing Trump for spouting "a load of nonsense."
Now Trump has a dilemma, whether to hit back in kind or take some other escalatory step or risk seeing his personal credibility and global authority damaged by a defiant Kim.
Trump's remarks were an example of his unorthodox approach to global leadership in action. He promised to be unpredictable and to prize force over nuance and to trash establishment doctrines -- and he has been as good as his word. But this is not a type of crisis Trump has ever faced before.
"What's he going to do about it? That's the problem with ratcheting it up," said Phil Mudd, a CNN national security expert, about Trump on "The Situation Room." "The President ratchets it up and the North Koreans say, 'OK, you have got a pair or twos, we have got three threes. We are going to put them on the table.'"
The sudden worsening of tensions is sure to set nerves on edge in North Asia and leaves the administration contemplating the first grave foreign policy crisis of Trump's term.
It is the first significant test for Trump's new chief of staff John Kelly and also of the President's own capacity to take a step back, to show patience and to seek a diplomatic way out of an increasingly unpredictable situation. In a dispatch that moved shortly after the threat by North Korea to send four missiles to within 30-40 kilometers of Guam, where there are two US military bases, Pyongyang's official news agency attempted to sharpen his predicament by mocking Trump personally as a "guy bereft of reason."
Wednesday's dramatic developments were the culmination of tensions that have been simmering perceptibly since even before the President took office, when his predecessor Barack Obama warned him off the deepening crisis that could reach a critical point on his watch.
Since then, Trump has fumed as North Korea has tested several intercontinental ballistic missiles. And he has turned the screw on China to do more to control its neighbor and become ever more bombastic in his threats and boasts on Twitter about the might of the US nuclear arsenal.
The result is that nearly seven months into his presidency, the world remains unclear about exactly where his policy stands, but fears are mounting that the US and North Korea could be on the cusp of a long-dreaded moment of brinkmanship on the Korean peninsula.
Trump's warning to North Korea on Tuesday followed the publication of a Washington Post report citing intelligence sources as saying Pyongyang had managed to miniaturize
a nuclear device to fit on an ICBM that could soon hit the US mainland.
But it was also a reminder that just a few words, delivered off the cuff from an outspoken President, can complicate the more orthodox diplomatic work of his administration, that in this case is starting to show some signs of progress after the passage of tough new UN Security Council sanctions at the weekend.
In a Facebook Live appearance, Republican Sen. John McCain rebuked Trump for his demeanor.
"I am not exactly sure that the President has fully appreciated that when he speaks," McCain said. "The most powerful person in the world -- his words reverberate all over the world."
Was there a plan?
The White House came under intense pressure Wednesday to answer a fundamental question -- did Trump just talk his way into a deeper confrontation with North Korea -- or was his intervention planned in advance?
Eventually, spokeswoman Sarah Huckabee Sanders said that officials, including Kelly were aware that the President would take a tough line if asked about North Korea on Tuesday by reporters.
"The words were his own. The tone and strength of the message were discussed beforehand," Huckabee said.
Secretary of State Rex Tillerson tried to play down the sense of crisis that Trump's phrasing provoked.
"I think Americans should sleep well at night," Tillerson told reporters as he headed home from Asia, saying he saw no sign the US had moved closer to a military showdown over the last 24 hours.
Part of Tillerson's mission was to finesse what Trump actually said.
One reason why the President caused so much consternation on Tuesday was that he appeared to draw a red line -- not just on North Korea's use of a nuclear weapon, or on constructing an ICBM, but just for continuing to issue the kind of threats that are the daily staple of the communist state.
Tillerson, not for the first time, artfully tried to reframe exactly what the President said: "I think the President just wanted to be clear to the North Korean regime that the US has an unquestionable ability to defend itself, will defend itself and its allies and I think it was important that he deliver that message to avoid any miscalculation on their part."
Mattis redrawing the red line?
Tillerson was not the only Trump official working on cleanup.
Secretary of Defense James Mattis later issued a written statement -- a method of communication that allowed him to spell out a stark message, but in a way that did not add to the sense of crisis.
"It must be noted that the combined allied militaries now possess the most precise, rehearsed, and robust defensive and offensive capabilities on Earth," Mattis said. "The DPRK regime's actions will continue to be grossly overmatched by ours and would lose any arms race or conflict it initiates."
Mattis's tough language appeared to be aimed at both North Korea and perhaps his own boss, in order to dispel any sense of disunity in the President's core foreign policy team.
But the defense secretary also appeared to subtly redraw the red line that the President established in his remarks on Tuesday.
While Trump warned of "fire and fury" as a price for North Korea's threats, Mattis said that the DPRK "should cease any consideration of actions that would lead to the end of its regime and the destruction of its people."
That could be read as a warning that any effort by Pyongyang to send a long-range missile America's way would lead to North Korea being wiped off the map -- a criteria for US action much narrower than Trump established on Tuesday.
State Dept. says everyone's on the same page
At the State Department, spokeswoman Heather Nauert offered a glimpse of the administration's efforts to try to inject some retrospective logic into Trump's Tuesday outburst.
"The President is sending a strong message to North Korea in the kind of language that North Korea understands," Nauert said, and also denied the administration was on different pages on how to deal with North Korea.
One of Nauert's predecessors, John Kirby, who now works as a national security analyst for CNN, said her comments were clear evidence of a crisis communications machine swinging into action.
"I think this is strategy after the fact, this is communications after it is already out," said Kirby. "The President says this crazy thing yesterday and everybody had to figure out how they react to it."