In his Discourses on Livy (Book III, Chapter 12) published in 1531, Niccolò Machiavelli argues that a prudent military commander must impose on his troops an absolute necessity to fight. He quotes Livy who refers to fighting through necessity as the “ultimate and most powerful weapon of all.” The late German-American political philosopher, Leo Strauss, commented on this very eloquently in his book, Thoughts on Machiavelli, (The University of Chicago Press, 1958). I found his argument so well made that I thought I would copy it below. (From pages 247-8).
[Machiavelli] gives some indications of what he understands by “such necessity” as make soldiers operate perfectly. To speak here only of Machiavelli’s primary examples, soldiers fighting against a superior enemy operate perfectly if they have no choice except to die or fight; they cease to operate perfectly if they can achieve safety by flight or surrender. To be driven by necessity means here to have no choice except to die or fight; for to have this choice means to have no choice at all since men are compelled by nature to try to avoid death; fighting is chosen because it is the only way in which in the circumstances certain and imminent death could possibly be avoided: the choice of fighting is imposed by necessity. If the soldiers can save their lives by flight or surrender, they choose flight or surrender as offering a greater prospect of avoiding death and as requiring a much smaller effort or as being easier. Fighting as well as flight or surrender aim at the same end, namely, the preservation of one’s life; this end is imposed, as we may tentatively say, by an absolute and natural necessity. If the enemy makes impossible flight or surrender, fighting is imposed on the soldiers in question as the only possible means to achieve the end mentioned. On the other hand, if the enemy gives them the opportunity to flee or surrender, flight or surrender is imposed on them as the better or easier means to achieve that end. Yet in the latter case, we do not speak of necessity prompting them because flight or surrender are easier than fighting, i.e., because they go less against the soldiers’ natural inclination. We shall then say that the necessity which makes soldiers fighting against a superior enemy operate well is the necessity, rooted in fear of death, to act against their natural inclination but within their ability. Generalizing from this, we may say that it is fear, the fundamental fear, which makes men operate well.
I think Machiavelli, as interpreted by Strauss, has made a compelling argument.