What if there really were a war on the Korean Peninsula? The rhetoric has been heated since the South Korean warship Cheonan was sunk by an explosion in March, killing 46 sailors, and it has been white-hot since investigators reported last month that a North Korean torpedo struck the vessel.
So suppose there is a local clash somewhere along the demilitarised zone between the two countries, or at sea along the disputed maritime frontier. Suppose it escalates. What would a full-scale war between North and South Korea look like?
We are told that North Korea has the fourth-largest army in the world, that it has heavy artillery within range of Seoul, and that it probably has nuclear weapons. So would an inter-Korea war be a calamity? Yes, but mainly for the North.
Imagine that the North Korean guns open on Seoul. The million-man army heads south, and the bulk of the obsolete air force takes off to support them. Meanwhile, a shower of short-range ballistic missiles, similar to the old Soviet-made Scuds, lands on command centres and air bases throughout the South.
What happens next depends on whether North Korea is using only conventional weapons. If it is, the attack fails quite fast. The North Korean air force is easily shot out of the sky, counter-battery fire and air strikes destroy the artillery, most of the Scud clones miss their targets, and the North Korean divisions are shredded by air power.
No modern army can survive without air cover. The South Korean and US air forces have around 600 modern military aircraft available in South Korea, and the United States can reinforce that number almost without limit in very short order.
A few hundred thousand North Koreans and a few tens of thousands of South Koreans would die, but nothing else of great moment would happen. It's not even likely that there would be a major counter-attack into North Korea.
But that's what would happen if the North Koreans used only conventional weapons. They undoubtedly have chemical and biological weapons in profusion and they would almost certainly use them. That would make the bombardment of Seoul a much uglier affair, since civilians would have little protection against nerve gas or lethal bacteria, but it wouldn't have much effect on the military outcome.
Nuclear weapons are a different matter, but it's far from certain that North Korea has any that would work reliably. More to the point, the nuclear retaliation of the US would effectively exterminate the entire regime. Since the North Koreans must know that, they would not act to bring that fate upon themselves.
So why did the North Koreans act so irrationally in sinking the Cheonan, if indeed they did? Nobody really knows, although they have long cultivated a reputation for dangerous unpredictability by doing such things.
But you can't help wishing that the 'independent investigators' who looked into the Cheonan's sinking had included at least a few Asians. In fact, why didn't they ask the Chinese to take part? They would have found it hard to say no.
Gwynne Dyer is a London-based independent journalist whose articles are published in 45 countries