It is not pusillanimity. If you are the lone society that tries to cooperate and spread peace you will be eaten out. It is rational and logical behaviour to survive.
If your goal is ideal world you must for a while be non-ideal to survive until you reach closer and closer to that ideal state. Which I would say we are doing currently.
Are we even moving closer to an ideal state? Lots of people make that claim but I think many that do have reason to defend the status quo even though many people today suffer from the status quo.
Just because some type of reasoning was used in order to justify something bad happening does not mean the reasoning itself is bad or wrong. If your goal is an ideal peaceful world you might have to be patient in order to reach it and take some non-ideal steps to have any chances at all reaching it.
And this is how fascism spreads. Thanks EstoniaTechLead for trying to seduce people into giving up their morality.
These are bad actions but for "the greater good"? You don't get to have it both ways. Protecting yourself without torturing people is 100% feasible and your argument should only be heard in a war crimes tribunal from the defendant'a lawyer to ease their sentence.
Morality isn't hard, but the implementation can be.
I deleted my previous comment, that assumed you reasoning is devoid of ethics. I don't know what "ideal world" or "non-ideal steps" you were implying, so I won't get into that. However, I can't stress enough how dangerous your line of thinking is. "The end justifies the means" is the poster-child for how tyrants justify atrocities.
Of which society do you speak of? The US?