Donald Trump took time out from his 17-day vacation at one of his golf resorts to threaten the nuclear obliteration of North Korea if they so much as make more threats against the U.S.- not if they actually attack the U.S.
"North Korea best not make any more threats to the United States. They will be met with fire and fury like, the world has never seen." And he said it twice, to make sure it's clear he was being deliberate and he meant it: "He has been very threatening beyond a normal state and as I said, they will be met with fire, fury, and frankly power the likes of which this world has never seen before." (Well maybe some other world has, eh?) 
So, did that fearsome warning of U.S. fire and brimstone stop the North Korean threats? Within an hour, NK responded with a threat to nuke Guam, a Pacific island and site of important U.S. military bases.
After the North Korean threat to blow up Guam, U.S. Secretary of State Rex "Big Oil" Tillerson rushed forth to make reassuring noises. He reinterpreted and distorted what Trump had actually said to pretend all Trump said was that the U.S. could defend itself. He told Americans they could "sleep well at night," meaning no danger here. And the governor of Guam, a U.S. colony (the U.S. calls its colonies "territories," to pretend it isn't imperialist), advised his subjects that they were in no "immediate" danger. (Like, there's no chance they'll die in the next 15 minutes.) 
But Tillerson's clean-up efforts were immediately undercut by "Defense" Secretary James "Mad Dog" Mattis, a former general, who immediately made another nuclear threat and sternly instructed North Korea not to try anything and to stop what it's doing, because that could "lead to the end of the regime and the destruction of its people."
In fact, for weeks Trump's "national security team" has been using threatening language against North Korea. Given the paranoid and fanatical and ultimately insecure nature of the regime, this is completely counterproductive. And since an actual attack on North Korea would be catastrophic for U.S. client South Korea, and very risky for the U.S., and sure to turn most of the world's population against the U.S., and create extreme hostility from China, it seems that the only sensible route is to try to calm North Korea, and strive for a reasonable goal like a freeze in North Korea's nuclear weapons program rather than abolition, in return for a peace treaty to formally end the Korean war and dialing down of U.S. military activity on the peninsula.
But that would be "weak." The U.S. is positively neurotic about "weakness." The most powerful nation in human history is actually quite pathetic in this regard. Instead of being confident in its strength, it feels that making any concession to an adversary is a gross humiliation. (Lyndon Johnson once referred to Vietnam as a dwarf with a knife which it would be shameful to not crush. The rhetoric is telling.)
What tripped off Trump's latest intemperate fulmination? Apparently an "analysis" from the DIA ("Defense Intelligence" Agency- now there's an oxymoron) that was planted in the Washington Post claiming that North Korea now had miniaturized a nuclear bomb so it could be put on a missile as a warhead, thus enabling it to actually attack U.S. territory with a nuclear weapon.
A word is in order here about the DIA's reliability. It stinks. One example should suffice to prove that the DIA can never be trusted:
During Saddam Hussein's aggression against Iran in the 1980s during the Reagan regime, the U.S. sided with Iraq because Iran had been taken over by Ayatollah Khomeini and the mullahs after overthrowing the U.S.-installed tyrant the Shah. Hussein used poison gas against Iraqi Kurdish villages. The DIA put out a report claiming Iran did it- a pure, conscious lie. In other words, the DIA put out what purported to be an objective, scientific analysis that was pure disinformation serving a hidden U.S. political agenda. And of course, when later Saddam was converted into an enemy, the gassing of the Kurds was hammered over and over as part of the indictment of how evil he was. (The U.S., both government and media, are nothing if not supremely cynical.) Naturally, the fraudulent DIA report was never mentioned again.
And generally, secret police agencies like the DIA are composed of manipulative liars and cynical power mongers, fanatical nationalists and ideologues whose objectivity is, shall we say, somewhat impaired.
As for the current DIA claim that North Korea has already miniaturized atomic bombs, something it was supposedly several years away from doing: Could it be that this is more DIA disinformation, designed to cause trouble? It wouldn't be the first time the U.S. military worked to provoke war. Ever hear of the Tonkin Gulf incident? ("Hoax" would be a more accurate term.) And the DIA is an extremely reactionary organ of the U.S. military. The fanatical Islam-hater Michael Flynn, briefly Trump's "National Security" advisor and now a target for allegedly playing footsie with Russia, was made head of the DIA by Barack "The Drone Assassin" Obama.
The Deep State, after all, considers itself the True Guardian of the National Interest. Presidents who don't go along with it are either manipulated to get in line, maneuvered around, painted into a corner, or neutralized. So who knows what byzantine plot the DIA may be up to?
Currently the U.S. Congress has been busily tying Trump's hands, forcing him to sign a law imposing additional punitive sanctions on Russia, barring him from firing the special counsel, grand inquisitor Robert Mueller III, and threatening to refuse to allow him to replace the Confederate racist Jeffrey Beauregard Sessions III as Attorney General. And the Deep State secret police agencies FBI, CIA, and the NSA, a military agency, have been planting damaging "information" against Trump, his family, and his minions, almost daily, in the media.
We just don't know if the DIA report is accurate or not. But the DIA is not trustworthy, so we can't assume one way or the other at this point. 
It would be worse than ironic if a nuclear war resulted from the U.S.' own disinformation. But then, the U.S. blew up the Twin Towers plus number 7 World Trade Center on September 11, 2001, and ever since has reacted to its own self-provocation with a global jihad against jihadism and the perfection of the world's most complete surveillance state ever.
1] Trump later added a false boast via Twitter, his favorite communication medium, that the U.S. nuclear arsenal is "more powerful than ever." (He does epitomize the unhealthy American obsession with power.) Actually the U.S. nuclear arsenal at its peak numbered 30,000 weapons, consisting of 20,000 strategic weapons and 10,000 "tactical" or "battlefield" nukes, such as atomic land mines, atomic artillery shells, atomic bombs carried in backpacks. The U.S. arsenal has been reduced to around 4,000 strategic weapons- still enough to destroy the world. Typically the atomic bombs are around 300 kilotons each- a kiloton denoting an explosive force equal to a thousand tons of TNT. A megaton is a million tons of TNT- the U.S. used to have megaton-range bombs, but with more accurate delivery systems and multiple bombs per missile warhead and bomber, the greater power was superfluous.
For comparison, the atomic bombs that destroy Hiroshima and Nagasaki in August, 1945, had estimated yields around 13 and 18 kilotons, respectively. The man who ordered those attacks on a defenseless, defeated nation, Harry S Truman (no period after the S, S wasn't a middle initial, S was the man's middle name, a fact that U.S. propagandists insist on obfuscating by putting an incorrect period where it doesn't belong) announced in part after obliterating Hiroshima, "If they do not now accept our terms they may expect a rain of ruin from the air, the like of which has never been seen on this earth." How very Trumpian. Or Trump is Trumanesque.
2] Guam is the site of U.S. military bases that are key to U.S. dominance over the vast Pacific Ocean. Its native inhabitants, ignorant simpletons, join the U.S. military, their conquerors, in large numbers. At some point they were made U.S. citizens, like Puerto Ricans, another U.S. island conquest and colony. Puerto Ricans have been used as U.S. cannon fodder since World War I.
3] The DIA is the creation of Robert S. McNamara. McNamara, the notorious Vietnam War criminal and Secretary of "Defense" (War) during the regimes of John Kennedy and Lyndon Johnson, was jealous of the CIA, and decided to create his own CIA inside the Pentagon, the DIA. (As if the U.S. needed yet another malign secret police organ.) McNamara was supposedly a real intellectual whiz, who headed Ford Motor Company prior to his government "service."
McNamara had experience as a war criminal long before the U.S. destruction of Vietnam, it turned out. We only learned this when McNamara spoke relatively candidly to documentarian Errol Morris. McNamara reminisced about his time as right hand man to general Curtis LeMay, the psychopathic mad bomber, during World War II. LeMay commanded a fleet of giant B-29 bombers (much larger planes than the famous B-17s) which he used to burn 67 Japanese cities to the ground prior to the atomic bombings of Hiroshima and Nagasaki. (His predecessor resigned the position as he couldn't stomach the requirement to slaughter civilians on a mass scale.) McNamara's role was to calculate the most effective way to torch the cities and immolate their inhabitants.
McNamara relates a particularly damning episode when LeMay said to him that if the U.S. loses the war, he and McNamara would be tried as war criminals.
According to Noam Chomsky, on the day Japan surrendered, LeMay launched a final 1,000 bomber raid on Japan, a particularly vindictive act.
LeMay went on to head the U.S. Air Force Strategic Air Command, the nuclear attack forces of the U.S. Air Force. He was an ardent advocate for nuking the Soviet Union, and later Vietnam. The fact that such psychopaths routinely rise to the top levels of U.S. power is quite revelatory about the nature of the U.S. system.