In 1950, a combination of ill-judged words in Washington and miscalculation in Pyongyang led to the outbreak of the Korean War. Now, as the world contemplates the prospect that another war might break out on the Korean peninsula, the danger is that governments in the US and North Korea will once again miscalculate - and slide into conflict.
Many historians trace the outbreak of the Korean War to a speech given by US secretary of state Dean Acheson at the National Press Club in Washington in January 1950. He spoke about America's "defence perimeter" in Asia - and suggested that Korea lay beyond the perimeter. In Pyongyang, North Korean leader Kim Il Sung took note of the clear implication that the United States would not defend South Korea. Five months later, his armies poured across the 38th parallel and invaded the South. But he had miscalculated. The US did fight. The Korean War cost hundreds of thousands of lives, led to direct fighting between US and Chinese forces - and has never formally ended. To this day, peace in Korea is maintained by an armistice rather than a formal peace treaty.
Where Mr Acheson signalled indifference, President Donald Trump is signalling resolve - vowing that the US will stop North Korea's nuclear programme and hinting heavily that he is prepared to take pre-emptive military action.
But once again there is a distinct danger that North Korea will lash out unpredictably. The country's leader Kim Jong Un, the grandson of Mr Kim Il Sung, has embraced his forebear's militarism, isolationism and paranoia. If the current Kim concludes that the US is indeed poised to attack his regime, he will be tempted to attack first. His incentive to move fast will only have been increased by stories in the media that the US' war plans involve an early attempt to kill the North Korean leadership.
North Korea's military doctrine, as expressed in recent exercises, envisages the first use of nuclear weapons to ward off defeat or destruction. Dr Jeffrey Lewis, an academic expert, wrote recently in Foreign Policy: "Kim's strategy depends on using nuclear weapons early - before the United States can kill him or special forces can find his missile units... He has to go first, if he is to go at all."
Although North Korea has not yet developed a nuclear missile that can hit the west coast of the US, it may well have nuclear-capable missiles that could hit South Korea or Japan. The South Korean capital, Seoul - which is just 56km from the North Korean border - is definitely vulnerable to a devastating barrage of conventional artillery. And Japan and South Korea are worried by North Korea's chemical weapons.
Mr Trump's heavy hints that the US is considering an attack on North Korea are designed to put pressure on China to "deliver" its client state on the Korean peninsula. This might work. The Chinese government is openly alarmed by events in North Korea and may pressurise Pyongyang much more heavily. It is also possible that the Kim regime is more intimidated than its outward swagger suggests and could yet freeze its nuclear programme.
But while it is certainly conceivable that the Trump administration's bellicose strategy could deliver, it is more likely that North Korea will not back down - and that the Trump strategy will therefore fail. In that case, the US President is faced with a dilemma. Does his "very powerful armada" steam away from the Korean peninsula, with its mission unaccomplished? Can the administration present an intensification of economic sanctions, possibly in conjunction with China, as the very tough action that it has promised?
Mr Trump is capable of shameless switches in rhetoric and policy. So it is certainly possible that he will simply back down on North Korea, or will embrace the status quo as the dramatic change that he has been seeking all along.
However, it is also possible that he has convinced himself that a first strike on North Korea is a workable option. Any such conclusion would fly in the face of standard military advice, which holds that it is impossible to "take out" the North Korean nuclear programme with a single wave of attacks and that therefore, following any such assault, South Korea, Japan and US bases in the region would be exposed to retaliation.
The US military is well aware of the risks entailed by a first strike on North Korea. So it is encouraging to recall that General H.R. McMaster, Mr Trump's National Security Adviser, has written a book lambasting US generals for not giving frank advice to politicians during the Vietnam War.
Set against that is the danger that Mr Trump - after a chaotic start to his presidency - has concluded that military action is the key to the "winning" image that he promised his voters. He lapped up the bipartisan applause that he got for bombing Syria. He dropped a huge conventional bomb on Afghanistan shortly afterwards and his son, Donald Junior, tweeted his exultation - complete with an emoji of a bomb.
There are members of the President's inner circle who do indeed believe that the Trump administration is seriously contemplating a "first strike" on North Korea. But if Mr Kim Jong Un has drawn the same conclusion, he may reach for the nuclear trigger first.