... exactly this contrast between the Franco-Prussian war (and Prussia's wars with Austria and Denmark shortly before, as well as other wars of the period). Because when the war started out, people did expect something like that - a few months, maybe half a year of fighting, a quick and clear victory for one side, and then some relatively modest demands in the peace treaty. And for a moment in late August 1914 when the French and the British Expeditionary Force were on the verge of letting the Germans break through to take Paris, while in the east the Russians were getting destroyed at Tannenberg, that outcome looked quite possible. Maybe a quick French/Russian defeat would've been better than what actually happened - then again, more likely it would just have led to a rematch down the line anyway. Perhaps not quite as spectacularly horrible and lethal as the WW1-WW2 combination, but bad enough.

But yeah, at the time Kerensky got to power, I'd say aside from more specific reasons, the biggest reason of them all to keep fighting was that everyone was in too deep. The losses has become too staggering to say, you know what, let's walk away from this and go back to the status quo. It's easy to see from our perspective how Kerensky should have sued for peace, even at a price higher than just the status quo, considering how the challenges for Russia were already so great even without the war and he needed all his energy and political capital domestically. But not surprising that it took a much more radical break with the past for Russia to get a government willing to cut its losses - a government that didn't identify much if at all with the one that had started the war and hence could ignore its war goals. In that sense actually a bit similar to Germany in the final months of the war in a much less dramatic way - they had to get various people out of the way before they could agree to the armistice.

Not just people in the US. But definitely of interest.