WHAT are WMDs? All right, easy. But what, precisely, is a weapon of mass destruction?

To a bowman at Agincourt, a tommy gun would be a wmd. Its big brother, the machine gun, able to mow down line after line of advancing troops like corn, as it did on the first day of the Somme, would be off the graph of "mass destruction".

Before gunpowder, the trebuchet, a giant sling that flung football-size stone missiles into castles, was a much feared instrument of war. Bombs that could lay waste a city would be beyond comprehension. And that a Dresden - and worse - could be produced by a single bomb, as at Hiroshima and Nagasaki, staggered the whole world less than a lifetime ago.

War gets bloodier with every generation. When it comes to devising methods of killing its own members there is no end to the devilish cleverness of the human race. A recent Bremner, Bird and Fortune programme captured this in a sketch in which the two Johns represented technologically-advanced planets that had perfected a weapon that would vapourise planets. Alarmed that primitive Earth was embarking on the same path with nuclear weapons, they zapped us out of existence.

But you cannot place a lid on advancing technology. The first users of gunpowder couldn't keep it to themselves. Now, more than half a century after Hiroshima, the nuclear genie, a dark force if ever there was one, is well and truly out of the bottle. Most of the major nations possess nuclear weapons, and the rogue state of North Korea is determined to join them. All the non-proliferation treaties in the world won't stop the spread of these WMDs. And, in time, the same will apply to space weapons.

Which brings us to Bush, Blair and Saddam Hussein. Essentially the action to strip Saddam of his WMDs is like attempting to squeeze the air from part of a balloon, which then simply bulges out elsewhere. OK, laying waste Iraq might deter other like-minded states for a while. But only for a while.

To maintain a situation in which only a select few hold WMDs will require endless wars from now until, well, probably doomsday.

Are we prepared for this? The only real hope is for the UN to become the effective counter to war that it was set up to be. This might require a permanent large UN army, something the UN has never had. But much more important is that the UN's members, especially the superpowers, act according to UN ideals rather than their own self-interest.

This would mean, for example, not supporting tyrants like Saddam Hussein, or the repressive Taliban, when it appears to suit. Despite the magnitude of the Iraq crisis, voting on the issue in the UN has been influenced by considerations of trade and "what's in it for us".

Saddam Hussein's inhumanities have been tolerated until his WMDs have become an issue. Even now similar inhumanities are being tolerated elsewhere. But the knowledge that such evil regimes would be world pariahs from the start might be the best way of squeezing them out of the system. Perhaps even the only way.

Yes, it's idealism I'm urging. But there is another word for it: sanity.

Published: ??/??/2003