The names of Asquith, Bethmann-Hollweg, Berchtold and Poincare are barely remembered, yet on any reasonable accounting they belong among the great criminals of history. Not only did they create the conditions for war, and rush (eagerly in most cases) into it, they carried on even as the death toll mounted into the hundreds of thousands and beyond. Even as the original grounds for war became utterly irrelevant, they continued to intrigue for trivial postwar benefits, carving up imagined conquests among themselves. Eventually, most were displaced by leaders who were marginally less mediocre, and more determined to win at all costs (Lloyd George, Clemenceau, Ludendorff, Hindenburg and others).
How could such ordinary, seemingly decent, men pursue such an evil and self-destructive course, and yet, in most cases, attract and retain the support of their people? I find it hard to understand.
Explaining WW1 involves taking into account factors that never go away;
1) Nationalist overconfidence
No nation really believes that its army isn't good enough to win, until it's proven.
2) Sunk costs fallacy
After the first year, settling for a draw (let alone losing) involved having traded a million or so dead for something that wasn't worth a million or so dead.
3) Party politics
Settling for a draw (let alone losing) involved, all the governments involved thought, the certainty of losing office and a high risk of bloody revolution and the overthrow of the whole society they knew. In which belief history shows they were more or less correct.
If the trenches had been on the French/German border it would have been a lot easier to stop. As it was, peace would have involved either Germany giving up a territorial advantage (when she hadn't lost) or France accepting a territorial loss (when she hadn't lost).
And it's all very well talking as if we moderns would have done the rational thing and saved all those lives. My grandfather fought at Gallipoli, and was in the charge of the Light Horse at the Nek, that most idiotic of doomed battles, four successive waves shot down instantly as they went over the top. At that point, the only way to stop the death of four hundred men would have been to for him bayonet a couple of officers on the startline, but if I'd been there instead of him I wouldn't have had the guts to do it and I rather doubt if JQ would have either. That's an extreme case, but it scales.