Good action counts for a lot.  But once a person has the ideology of power fixed in their head, they can never feel safe enough. Goodness flies out the window. There is never enough power, never enough wealth.  It is not the imperative of greed, it is the imperative of survival.  Technology now allows us to survive without willful cruelty and domination, but that does not make sense to power-driven individuals.  They want the power and the glory.

So what do we do about the callous power-centred leaders of most countries whose desire for control and personal wealth is unrestrained?

That’s a trick question.

“We” never do anything. 

If “we” have any influence at all, it is to sustain and support the existing social system. “We” are responsible for those leaders … for the way they think, how they got into such positions, and why they stay there.  So the British “we” is responsible for UK atrocities not the PM and cabinet; the German “we” was responsible for Nazism in Germany not Hitler; More...

«Egoism and altruism» is a hardy perennial of philosophers and now a staple for academic psychologists.  Are people basically self-interested or basically concerned for others?

Trick question.  Once the issue is posed like this, any hope of understanding oneself or acting sensibly is lost. 

People act in their own self-interest.  They must.  Some are certainly more self-centred than others.  People are also capable of concern for others and demonstrate benevolence.  They must.  Otherwise it would be hard to live in groups.  Again, there is variation amongst people in the degree of altruism.  For some of you, it might be hard to live with yourself if you were irredeemably selfish. 

The issue is never what academics or philosophers assert people 'are'—and which, supposedly, is what you are or what I am.  The issue in real life is always about what am I going to do at this moment in this situation given who I am.  The variations here are almost infinite.

Yes, we do have tendencies and styles.  But we are not More...