By MAX HASTINGS
THE SEISMIC shock has echoed around the world.
Its reverberations are shaking capitals.
North Korea's atomic bomb test has enraged Washington, exasperated Beijing, frightened Tokyo and Seoul, and struck a devastating blow at efforts to check nuclear proliferation.
Until now, even those accustomed to Kim Jong-Il's brinkmanship supposed that he might hold back from an action which overnight intensified his isolation.
The International Institute of Strategic Studies believed that for Kim to test a bomb would be a 'suicidal' course of action.
Conventional wisdom had it that even if he was willing to defy American wrath, he still deferred to China, the nearest thing he possesses to a friend. Now, however, the Chinese leadership seems as appalled as everybody else - and as unsure about what to do next.
North Korea keeps a million men under arms. Most of its 31,000 artillery pieces are deployed within range of the South Korean capital, Seoul. It possesses biological weapons and up to 5,000 tons of chemical weapons. Its leader is apparently willing to do anything, absolutely anything, to preserve his mad regime.
Kim Jong-Il cares nothing that North Korea's economy is in ruins, and most of its people starving.
He believes nuclear weapons offer the only threat capable of dissuading the Americans from military action against him, and of blackmailing the West into giving his country cash and food.
The fate of Saddam Hussein strengthened his belief that only Weapons of Mass Destruction can ensure his own security. It is a bold man who today asserts that he is wrong.
Since the Russians occupied North Korea in 1945, the country has been a communist little hell. Stalin installed in power Kim Jong-Il's father, Kim Il Sung, and encouraged him to invade South Korea in 1950. This provoked war with United Nations forces led by the Americans and the British.
In the 53 years since the conflict ended in stalemate, Kim Il Sung - and, since his death in 1994, his son - have preserved North Korea as a Stalinist time capsule. While communism collapsed elsewhere, the Soviet Union broke up and China embraced much of market capitalism, North Korea changed nothing.
The Kims have kept their country on a permanent war footing, starving the population to feed their huge army.
Dissent is rewarded by death.
The ruling class, which embraces not only party chiefs but 150,000 secret policemen, live in corrupt comfort while some peasants are reduced to eating grass.
Smuggling, extortion, money laundering, currency forgery, kidnapping and weapons trading are North Korea's principal industries.
The regime has survived only because China has indulged it.
Although the Chinese have gone far down the capitalist route, they still profess a commitment to state socialism. The Beijing leadership has refused to abandon its oldest client.
South Korea is deeply equivocal about its northern neighbour. It is almost as fearful of the consequences of Kim Jong-Il's fall, of finding 23million destitute fellow-Koreans on its doorstep, as of the military threat Pyongyang poses today.
Younger South Koreans, especially, resent what they perceive as American attempts to bully Asia. Successive Seoul governments have striven to avoid a showdown with the North, and strongly criticised America's hard line.
Until 1945, the Japanese ruled Korea with conspicuous brutality. Today, they are intensely fearful of the monster a few miles across the sea.
This summer, Japan imposed sanctions on Pyongyang after Kim staged missile tests. It is likely that Japan will now tighten its economic squeeze.
After 60 years as a committed non-nuclear power following the traumas of Hiroshima and Nagasaki, Tokyo might soon review this policy.
The foremost historic consequence of the test could be that Japan is no longer willing to live beside a wildly unstable nuclear-armed neighbour without a deterrent of its own.
And the United States?
Where is George Bush, on this sorry day for global stability?
In Iraq, of course, trapped in a conflict which has disastrously crippled not only the might, but the moral authority, of the world's only superpower.
Many argued before the 2003 Iraq invasion that its worst consequence would be to weaken U.S. ability to deal with North Korea and Iran, both of which represented far more serious threats than Saddam Hussein. So, indeed, it has proved.
If there was ever a military option for dealing with Kim Jong-Il, it no longer exists.
Whatever cries of outrage the White House delivers about Kim's nuclear test, America cannot undertake military action to disarm the North Koreans.
The practical problems of targeting and destroying their nuclear installations - mostly underground - are very great.
The political difficulties are insuperable.
Because of Iraq, the world has lost faith in Washington's judgment and the U.S. has not a dollar's worth of moral capital in the bank to deploy against Pyongyang.
Henceforward, everything turns on what Beijing, not Washington, does about Kim Jong-Il's nuclear virility display.
The Chinese authorities have condemned the North Korean action as 'brazen'.
Yet nobody pretends to know whether their leaders will act vigorously against their ally. The bomb test offers China a huge political opportunity. If Beijing proves willing to act decisively, to pull the plug on Kim - and without Chinese economic support, it is impossible to see how his regime could survive - then China could achieve a huge victory.
Imagine the international response, if Asia's new master nation proved able to defuse the threat from a rogue state that is terrorising a continent.
China's prestige would soar, while that of the United States would suffer a corresponding blow.
But it is impossible to gauge whether the wary old men in Beijing have the stomach for tough action. They may instead choose to leave Kim strutting on his perch, highlighting America's impotence.
Beijing could well decide that it prefers North Korea as a source of fear and embarrassment to the West, rather than decapitated and in chaos, with millions of starving refugees pouring across the Yalu river border into China.
What is certain is that Monday's event represents the worst possible news for the world's shrinking hopes of preventing nuclear proliferation.
The Americans acquiesced in Israel's acquisition of bombs, more recently in India's and tacitly in Pakistan's.
It was India's chief of defence staff who said after the 1991 Gulf War: 'The message is that no country can resist the United States unless it has nuclear weapons.' America's enemies took heed. Most of the world believed in 2003 that George Bush would not have dared to invade Iraq, had Saddam possessed a bomb. Kim Jong-Il has this week made himself almost invulnerable to military attack. Iran is eager to follow suit.
Kim Jong-Il is a tinpot tyrant, but his possession of nuclear weapons makes it impossible to ignore him. It is a reflection of the shocking weakness to which President Bush has reduced his great nation that only Beijing, not Washington, can bring Kim down.
What happens next will represent a critical test of China's will to play a responsible part in promoting global stability. It is hard to be optimistic about the outcome.
