The pro-war-novel-of-high-literary-merit category seems to be rather thin.
The only nominee so far that seems to fit the bill is one I hadn’t read by an author I hadn’t heard of, Ernst Junger’s Storm of Steel, a fictionalized WWI memoir from the German side. Mark Helprin’s work was also mentioned, though not a specific novel. One reader nominated The Red Badge of Courage, which I recall as being anti-war.
Science fiction and fantasy of course provided serveral examples, including Starship Troopers, Ender’s Game, The Worm Ouroboros, and The Lord of the Rings. But if it’s necessary to create distance by inventing times, peoples, geographies, and battle styles before one can write about war approvingly, that seems to rather make my initial reader’s point.
I think the same is true of historical fiction; someone writing today about Napoleonic naval warfare isn’t writing about the wars we now fight. Gore Vidal’s Julian, written from the viewpoint of a successful general, is in the same category.
Le Carre was also mentioned, and Deighton and Buchan might have been, but spying isn’t combat. Deighton’s war fiction, especially the stories in Eleven Declarations of War, seems to my eyes undoubtedly of high literary merit, and it’s certainly not antiwar in any obvious way, but, as in his spy fiction, the focus is on interpersonal relationships in a bureaucracy rather than on the activities of killing and of avoiding being killed.
One reader pointed out that a polemically pro-war novel probably wouldn’t be very good as a novel. That’s probably true, though it doesn’t explain why so many people have written polemically anti-war novels.
But then the Iliad isn’t polemically pro-war, either. I don’t think the original questioner was really looking for novels that argued the case for war or that pointed out that war might have good effects on some of its participants.
The key is elsewhere. The striking thing about the Iliad that seems hard to match in modern literary fiction is the acceptance of the feats of war as worth praising on their own technical merits. The combat scenes in the Iliad resemble nothing more closely than sportswriting, unless it’s sportscasting.
When I was growing up, there were comic-book series (GI Joe is the name I remember) that took the Homeric attitude toward the combat of World War II and Korea. Each story was a battle anecdote displaying courage and ingenuity in action in the persons of American combat troops. The reader was intended to identify with the characters, just the way the reader of juvenile sports fiction is intended to identify with the players.
At a much higher literary level, Garrett Mattingly does the same thing with naval combat in The Armada, though the focus is on the commanders rather than the sailors. In any case, that’s history, not fiction.
The celebration of battle feats is, it seems to me, the “pro-war” feature that’s present in the Iliad and absent in, say, War and Peace. Tolstoy certainly glorifies Kutuzov and intends the reader to be pleased by Napoleon’s defeat. But Tolstoy doesn’t put you in the shoes of a Russian artilleryman and ask you to admire his coolness under fire or his brilliant improvisation after his horse gets shot.
So I think my reader’s point stands: the Homeric attitude toward warfare is impossible for the modern novelist to reproduce.