The number of American troops in Vietnam peaked in 1969. Twenty years later, Born On the Fourth of July, which dramatised the maiming and political awakening of one soldier, came out. Even after Platoon, The Deer Hunter, Full Metal Jacket and Apocalypse Now, even after the protest songs of Edwin Starr and Creedence Clearwater Revival, artists weren’t done with the subject.

Now consider the Iraq war. Twenty years on, its cultural footprint consists of . . . what? The Hurt Locker? A sub-theme in some passable novels?

Yes, US casualties were far higher in Vietnam. Yes, a conscript war scars a society in a way that an all-volunteer one can’t. But Iraq was easily the most controversial war fought by a western state in the past half-century. It set citizen against citizen in Britain and Germany as much as in the US (no European nation participated in Vietnam). Those who lived through it might have assumed it would mark our culture for a generation: that pro and antiwar would become signifiers of one’s wider worldview, even one’s tastes, as Leave and Remain now are in the UK. Instead, it is often an ordeal to persuade the young what a saga it all was.

And that, I think, is what makes this 20th anniversary so eerie. At least within the western world, the Iraq war has left little trace.