Updated March 14, 2017 16:30:07

It is a ritual almost as old as the Korean War itself.

Every year, the Americans and the South Koreans hold joint military exercises along the demilitarised zone between the North and South.

And at the same time authorities in the workers' paradise on the northern side of that border denounce the drills as war-mongering and a threat to their existence.

There is usually an accompanying verbal assault promising the fires of hell will be opened up and consume the would-be invaders from the South.

And in that time-honoured tradition, this year the North Korean Ambassador to the United Nations, Kim In-ryong, said:

"The US and South Korean forces kick off the joint military manoeuvres aimed at a pre-emptive nuclear strike against the DPRK [Democratic People's Republic of Korea] only to push the situation to the brink of the nuclear war."

The rhetoric may sound familiar but this year is different, because authorities in Pyongyang decided to send more than just threats.

Four ballistic missiles were fired towards Japan's north-west coast.

They were not armed with nuclear weapons but they could have been.

And that was the intended message from the North — back off or we might just decide to attack Japan or South Korea with nuclear weapons.

And of course, Japan is the only country in the world that knows the consequences of a nuclear attack.

Photo: "Pukguksong-2" was launched at an undisclosed location in North Korea on February 12. (AP: Korean Central News Agency/Korea News Service)

Regime looks more unhinged than ever

Ambassador Kim In Ryong defended the missile tests as "the defensive right of the sovereign state to keep on high alert as required by the Korean situation, in which actual war may break out anytime and to consolidate a powerful deterrence and in every way to mercilessly to wipe out the oppressors."

Add to that the apparent nerve agent murder of North Korean leader Kim Jong-un's half-brother in Malaysia and the always unpredictable regime in Pyongyang looks even more unhinged than ever.

That wouldn't matter so much if they did not possess nuclear bombs and the means of delivering them.

Officials and independent experts all say Kim Jong-nam's assassination looks like the work of North Korean agents.

It has so unnerved the United States that it is reviewing its entire approach to the hermit state including, presumably, the military option of a first strike.

That will no doubt be discussed when the US Secretary of State Rex Tillerson travels to Japan South Korea and China for what could prove to be decisive talks about how to handle the region's delinquent neighbour.

At the same time, the Americans are boosting South Korea's defences, deploying Terminal High Altitude Area Defence (THAAD) anti-missile systems, aimed at destroying missiles launched from the North.

Also adding to the arsenal are so-called "killer drones" that will become standard issue along the world's most militarised border.

"These are very clearly defensive measures that we're taking in response to an increasingly worrying, concerning threat from North Korea," US State Department spokesman Mark Toner said.

"China understands that threat. We're doing the utmost that we can do for not only the defence of our forces, but for the defence of the Korean people."

China does understand the threat, but is fiercely opposed to the anti-missile system being deployed in South Korea because it sees it as an encroachment of US firepower in its strategic backyard.

Combined with the posturing on both sides over China's contentious South China Sea territorial claims, it will ratchet up tensions between two major powers.

US has decided enough is enough

Yet there is possibly room for agreement on North Korea, at least.

The Kim dynasty is long and bloody. Here's who's who in North Korea's ruling family

Neither side would benefit should war break out.

From the American perspective, things cannot go on as they have.

The fear is previous hollow threats from Pyongyang look increasingly dangerous as the level of unpredictability soars unsustainably high.

The future security, or lack of it, depends in large measure on the unfathomable thoughts of one man, Kim Jong-un.

The US has decided enough is enough.

Just how Rex Tillerson plans to rebalance power in that volatile peninsular is yet to be revealed.

North Korea has always traded on regional fears its leadership is just crazy enough to provoke a potentially catastrophic war.

That strategy may be called out by the Americans, but what happens next is impossible to predict.

Topics: world-politics, government-and-politics, unrest-conflict-and-war, korea-democratic-people-s-republic-of, united-states

First posted March 14, 2017 16:12:23