I have been reading some of Leo Tolstoy's short stories and novellas lately. The beginning of the short story The Raid channels Gordon Tullock's work on military tactics (with Geoffrey Brennan) as well as on revolutionary movements, asking "under the influence of what feeling one soldier kills another". Tolstoy goes on to explain how being a soldier often implies great risks to one's life, and that rage is a poor reason to join the army, since it can hardly be sustained over the course of a military campaign. Tolstoy also posits that the killing of fellow men in war serves no purpose, an idea which likely comes from his pacifism, but is left unanalysed.
Enter Gordon Tullock and methodological individualism. Joining a revolutionary movement or taking part in a military campaign is highly unlikely to affect which side is victorious, so from the individual's point of view, one is essentially producing a public good for those cheering on the side one joins. There is nothing explicitly pacifist about this idea, although it seems to fit Tolstoy's position quite neatly. So why do individuals choose to join the military or a revolutionary movement?
One potential explanation is that they are offered private benefits for doing so (as opposed to the public goods which may come out of the successful toppling of a cruel regime). I am blissfully lacking any personal experience with army life, but it seems conceivable to me that volunteers are not made to march in the front lines and may be promoted (to safer positions) more easily than are conscripted soldiers.
In support of this thesis may be said that during the Winter War of 1939-1940, in which many non-Finns, Swedes in particular, volunteered on the side of Finland against the Soviet Union, the death rate for Finns was a little above seven per cent, while that of the foreign volunteers was less than half a per cent (according to Wikipedia's 'Winter War' article: see the box in the top left corner, as well as the section 'Foreign Volunteers'). There are several other interesting conflicts from which similar evidence may be obtained. For instance, there were many foreign volunteers in the Spanish Civil War. If anyone has good numbers on related conflicts, or even interesting anecdotes, I am all ears.
Going back to The Raid, Tolstoy talks about an apparent indifference amongst soldiers to their possible impending demise. There is even some joy expressed at the prospect of fighting, and those who are not involved appear glum. Tolstoy (who, incidentally, fought in the Crimean War) does not say this, but maybe these instances reflect strategies by conscripts to show valour to officers and increase their chances of promotion? This does not reflect attitudes by characters in other books by Tolstoy (for instance, remember Petya Rostov in War and Peace?), but maybe it does a better job at reflecting reality?