I can discern certain Nietzschean undertones such as Undershaft's idealization of the will to power. I also understand Undershaft's discussion on the problem with describing poverty and starvation as virtues, and how the Salvation Army essentially bribes the poor with bread as opposed to actually saving their souls. Sure, that may dismantle the moral position of Cusins and Barbara, but how does it contribute to his own position? He manufactures weapons and self-admittedly sells to all indiscriminately. It seems to be a non-sequitur when he says
"[killing] is the final test of conviction, the only lever strong enough to overturn a social system"
because he - by his own admission - shouldn't have any qualms in providing that "social system" with firepower. I don't really understand the main argument he is using by the end of the book to persuade Cusins and Barbara. Why were they persuaded?