In the wake of Robert Lowell

Can today's poets seize the moment as their great predecessors did during the First World War and th

Weekly assembly at my old school in Essex was a sombre, repetitive occasion. A recital of the Lord's Prayer, a homily or two from one of the senior masters, the obligatory warnings about the consequences of meddling with cigarettes or alcohol: it was an event that one tried to avoid.

One assembly, however, was different. It took place shortly after the Soviet invasion of Afghanistan. The aged headmaster, a short bald socialist, walked on to the stage before us and, without explanation, read the following lines: "Bent double, like old beggars under sacks,/Knock-kneed, coughing like hags, we cursed through sludge,/Till on the haunting flares we turned our backs,/ And towards our distant rest began to trudge . . ." We sat silent, compelled by our first encounter with one of the great anti-war protest poems, Wilfred Owen's "Dulce et decorum est", with its scathing irony and visions of gas-poisoned soldiers.

The First World War is a peculiarly, perhaps uniquely, literary war; the poems of Owen, Siegfried Sassoon, Edmund Blunden, Isaac Rosenberg, Ivor Gurney and others are among the first that most of us ever read. The shock and immediacy of these visceral, often homoerotic poems have helped to create a popular conception of the Great War as one continuous, remorseless exhibition of atrocity. Our image of the combatants, too - of innocent boys with "froth-corrupted lungs", led to their slaughter by an arrogant military elite - derives mostly from the poetry.

Other artistic media - the shattered landscape paintings of Paul Nash, the novel All Quiet on the Western Front, the play Oh! What a Lovely War, which emerged out of the counter-culture of the 1960s, even the celebrated final episode of Blackadder Goes Forth - have contributed to a literary cult of doomed youth and to the idea that the First World War was an evil thing. Yet if you listen to the historian Lyn Macdonald - who spent more than two decades recording 15,000 interviews with veterans - the experience of the common soldier was altogether different. Instead of the cliche of the "horror of war", they talked about the boredom and confusion of combat, the weeks of inactivity interrupted by abrupt skirmishes, and of the "adventure" of battle itself.

"I have nothing against the war poets," Macdonald told me. "By definition, their work distils the war to the essence of drama. But they focus on the terrible events at the expense of the whole truth. What has to be remembered is that most of our soldiers were volunteers; they believed in their country and in the empire. They thought that these things were threatened. They were also caught up in the adventure of the experience. Every veteran I ever interviewed, I asked the same question: 'Would you do it again?' Not one said no."

Today, poetry occupies an enfeebled position in our culture; it has been supplanted by pop, television and film, by the clamour of commerce and celebrity. Yet the longing for the heightened lyrical expression of complex thought and emotion remains deep, as is evident during periods of great national trauma. And there has been an attempt of late to reinvent the idea of the poem of public protest. Andrew Motion, in particular, wants to redefine the role of poet laureate, so that he becomes less a poet of monarchy than a national poet, free to write about whatever or whichever institution he chooses.

The modern poet, according to Motion, has a responsibility to be politically engaged. He should seek public commissions, as Ben Okri, Harold Pinter and Tom Paulin have done in expressing their opposition to war in Iraq. The poet should seize the day, by writing to, and about, the moment. Poetry, in this model, is about much more than emotion recollected in tranquillity; it has the potential power and urgency of the best journalism or pop music.

Protest poetry has a long and noble tradition, which, more recently, includes the poets of the Great War; those such as W H Auden and Stephen Spender who wrote so well about the Spanish civil war; and Robert Lowell's anti-Vietnam poems.

In 1967, as the crisis deepened in Vietnam, Lowell stood before a crowd of anti-war demonstrators in Washington and read his great poem "Waking Early Sunday Morning". It is about the loneliness and responsibility of America, a country whose imperial ambitions doom it "to police" the world. The final stanza is memorable: "Pity the planet, all joy gone/from this sweet volcanic cone;/peace to our children when they fall/in small war on the heels of small/war - until the end of time/to police the earth, a ghost/orbiting forever lost/in our monotonous sublime."

Lowell was received that day with rare rapture and delight. Could the same happen today? It is impossible to imagine that Andrew Motion would be similarly well received if he ever chose to read an anti-war poem before assembled thousands in Trafalgar Square. I may be wrong. In any event, we shall soon discover just how important poetry can still be to our nation at war.