Donald Trump's nuclear fixation - from the 1980s to now

Protesters outside the White House call for a de-escalation in tensions

Donald Trump's warning that North Korea could face "fire and fury the likes of which the world has never seen" has been widely interpreted as a threat backed by the destructive power of the US nuclear arsenal.

In case that message wasn't clear, the following morning the president boasted that US nuclear weapons were "far stronger and more powerful than ever before".

"Hopefully we will never have to use this power," he tweeted, "but there will never be a time that we are not the most powerful nation in the world!"

The president's recent nuclear sabre-rattling shouldn't be viewed as an isolated incident, however. Mr Trump has displayed a keen interest in the utility of atomic weapons for decades.

It's part of a political worldview that has long since solidified into firm beliefs for the septuagenarian. His thoughts on trade have been influenced by the American industrial might of the post-World War Two era. His demographic views of the nation hark back to an ethnic homogeneity that has long since vanished. And his thoughts on atomic weaponry reflect a certain strain of Cold War arms-race enthusiasm and diplomatic brinkmanship.

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Last December President-elect Trump emphasised that the US had to "greatly strengthen and expand" its nuclear weaponry and would "outmatch" any adversaries.

In August MSNBC's Joe Scarborough reported that candidate Trump had asked his foreign policy advisers several times why the US couldn't use its nuclear weapons - a claim the Trump campaign denied.

The report, however, followed on the heels of an April 2016 town hall forum exchange between Mr Trump and MSNBC's Chris Matthews, who asked him why he had refused to categorically rule out the use of nuclear weapons.

"Would there be a time when it could be used?" Trump replied. "Possibly. Possibly."

When pressed on the risks of openly talking of using nuclear weapons, Mr Trump said: "Then why are we making them? Why do we make them?"

(The US no longer makes new nuclear warheads. It maintains its current arsenal.)

He repeated that he is not going to take any of his "cards off the table".

Digging back further, in 1990 Mr Trump gave an interview with Playboy Magazine in which the topic of atomic weaponry came up.

"I've always thought about the issue of nuclear war; it's a very important element in my thought process," Mr Trump said. He called it the "ultimate catastrophe" and compared it to an illness no one wants to talk about it.

"I believe the greatest of all stupidities is people's believing it will never happen," he continued, "because everybody knows how destructive it will be, so nobody uses weapons. What [expletive]."

US troops regularly hold training drills with South Korea

In 1984 - at the height of the Cold War - Mr Trump even told a Washington Post interviewer he wanted to be put in charge of US-Russia nuclear arms negotiations.

"It would take an hour-and-a-half to learn everything there is to learn about missiles," Mr Trump said. "I think I know most of it anyway."

Around the time of this interview a computer game called Balance of Power, which simulated the Cold War struggle between the US and Soviet Union, became a surprise hit.

Players could sabotage, scheme and sabre-rattle up to the brink of nuclear war. The trick was you were never quite sure how close you could get before the missiles started flying. Escalation could lead to inadvertent annihilation.

And if it did, this was the message, displayed in white letters on a black screen: "You have ignited an accidental nuclear war. And no, there is no animated display of a mushroom cloud with parts of bodies flying through the air. We do not reward failure."

If Mr Trump's past comments are any guide, he appears to be making the calculus that the US nuclear arsenal is ineffective if adversaries don't believe the nation is willing to pull the trigger. It's all part of the "unpredictability" strategy he repeatedly touted during his presidential campaign (and plugged again in a recent tweet).

Mr Trump - and his Defence Secretary Jim Mattis - have spoken of how the US will prevail in any military confrontation with North Korea. Largely left unmentioned amid the bluster, however, is the danger that an extended standoff could spin out of control and the high cost in human lives - in civilian lives on both sides of the Korean demilitarised zone and for US military personnel - that any such conflict would entail.

The US would almost certainly prevail, but it would be difficult to view such a result as anything but a failure.