Poetry Guide: War Poets
The term war poet came into currency during and after World War I. A number of poets writing in English had been soldiers, and had written about that experience. Quite a number had died, most famously Rupert Brooke, Wilfred Owen, and Charles Sorley. Others such as Siegfried Sassoon had survived, but made a reputation based on scathing poetry written from the disabused point of view of the trench soldier who had lost faith in his military superiors. At the time the term soldier poet was also used, but then dropped out of favour.
World War I
There was probably at least as much poetry of quality written on the German side of the Western Front; but it was in English poetry that the war poem became an established genre marker, and attracted growing popular interest. Americans and Canadians contributed notable work (John McCrae wrote In Flanders Fields which is on the Canadian $5 bill), and the French had their own war poetry. According to Patrick Bridgwater in The German Poets of the First World War, the closest comparison to Owen would be Anton Schnack; and Schnack's only peer would be August Stramm.
It is perhaps not a well-defined question, what makes a war poet (compare, say, Brooke and Georg Trakl). The public may have seen war poems as reportage and direct emotional links to the soldier. Robert Graves served in the trenches and survived, David Jones also; Graves did not use war experience as poetic material (making it autobiography in Goodbye to All That), or, more accurately, later suppressed what he had made of it; and Jones postponed its use, incorporating it into modernist forms. These and other WWI poets are listed here: World War I poets.
Spanish Civil War
The Spanish Civil War produced a substantial volume of poetry in English and, of course, Spanish too, and other languages — there were English-speaking poets serving on both sides.
World War II
By the time of World War II the role of 'war poet' was so well-established in the public mind that 'where are the war poets?' became a topic of discussion. The Times Literary Supplement ran an editorial 'To the Poets of 1940' right at the end of 1939 (still during the phoney war, therefore). Robert Graves gave a radio talk 'Why has this War produced no War Poets?' in October 1941. Stephen Spender also replied at about the same time, T. S. Eliot a year later.
Alun Lewis and Keith Douglas are the standard critical choices amongst British war poets of that time, and Karl Shapiro made a reputation based on poetry written during the Pacific war; there was probably more heavyweight poetry written in French from 1939-1945, than in English. The reason may be to do with the onward march of technology and the fact that soldiers spent less of their time sitting in trenches waiting for something to happen.
The expectation of war poetry can be noted in a character from the C. S. Forester novel The Ship who is a poet serving in a Royal Navy ship in the Mediterranean around 1942, and who is killed in action. Benjamin Britten's War Requiem made use of war poem texts, as does Robert Steadman's "In Memoriam".
There has been little recognition of war poetry from any subsequent conflict, certainly when compared with novels. That is not to say, at all, that such conflicts have not affected poets and what they write.