Several weeks ago I visited with my family the Soldiers' Memorial Museum in the heart of downtown St Louis. It is a huge and deeply impressive building, dedicated in 1936 by President Franklin D Roosevelt as a memorial to the 1075 men of St Louis who died in the First World War. The memorial is painfully beautiful, all mosaics and marble, with terrazzo floors and Bedford stone sculptures. It is dominated by the vast black granite cenotaph in its center, covered with the hundreds of dead men's names in neat row upon neat row.

On the day we visited this striking but haunted place it seemed completely empty. While empty of visitors, it was however full of the spirits and the voices and the faces of the pale, tousle-headed boys in neatly-pressed uniforms who had marched off from St Louis 86 years ago to fight in a glamorous and glorious war in a far-off land. Boys who had never come back home. The poignancy of that was rendered all the stronger by the fact that we are living daily with the repercussions of a current conflict, the savage and bloody war in Iraq. We read daily of boys who will never come back home.

What struck me most as I walked around the memorial and the museum, holding my newborn baby girl, was the fact that it looked just like so many of the war memorials that I had visited in my home country of Scotland. It also looked just like those I had visited in France, and in England, and in Canada, and in New Zealand. And it looked just like the memorials in almost every other country touched by the carnage of World War One. In almost every country that took part in that war - the so-called "War to End all Wars" - men rushed to join the military and marched off to war with great enthusiasm. They believed that it would be a short, sharp and successful war, fought for good reasons, and glorious for the winners. They believed that they were building a better world.

They were wrong. An average of 5,500 men died every single day for four and a half years in the First World War: that's roughly four men per minute, every minute, for four and a half years, until some 9 million men were dead. The First World War did more than just destroy lives; it destroyed the confidence in progress, in prosperity and in the reasonableness of civilized human beings that had become so characteristic of the nineteenth century. That war destroyed much of the next generation which would have provided leadership to Europe in the dark days of the twenties and thirties when the world flirted with the dark seduction of Fascism and once again Europe began sliding towards holocaust and Armageddon. And that war should never have been allowed to happen. It was the worst of all disasters, the disaster that could have been avoided.

And this morning, as I sit holding my baby girl and read daily reports of escalating violence in Iraq, with Iraqi, British and American men and women continuing to die, the St Louis Soldiers' Memorial - a memorial to a war that should have never been fought - haunts me. The neoconservative brains in the U.S. administration would have been wise to visit places like this and to think long and to think hard about the lessons of such memorials before embarking on a war in the Middle East that has already killed unknown numbers of people, and which will certainly kill many more, directly and indirectly.

Despite some superficial stylistic differences, every war memorial ultimately teaches the same lesson. The lesson is that whatever the cause, the fate of the young men and women who fight is the same. Whether the cause is that of Jesus or Muhammad, of oil or gold, of territory or sovereignty, the end result for the soldiers on the ground is always the same. Whether the battle is won or lost, and whether the war is successful or not, it is the common soldiers whose names end up, in neat row upon neat row, carved into the granite of war memorials all over the world. Having died among disorder and chaos, their names find order and dignity on marble slabs.

I believe that these words of Mayor Bernard Dickmann of St Louis, speaking when the Soldiers' Memorial was opened to the public in 1938, have great potency for us today: "We who live, because others have died, should make of this shrine a place of love and a monument of peace." Those neoconservative analysts who planned the war, the politicians and pundits who clamored for it, the businessmen who scrambled for the resultant profits, and the TV analysts and anchors that spoke with barely concealed glee about "shock and awe," should go to St. Louis. They should spend some time in silence at one of this nation's most poignant war memorials, reading the names of the naïve but well intentioned young men who died in one of history's most meaningless wars. Then, perhaps, the Soldiers' Memorial Museum could indeed become "a monument of peace." Then, perhaps, my baby girl could grow up in a world that is not ravaged, raped and wrecked by shortsighted and ill-considered wars.