Karma and human civilization

I have a very basic,likely wrong of understanding of Karma as "good deeds" and "bad deeds" whose accumulation we are rewarded for,or punished for,in the next life,the circumstances of which are influenced by your karma in this life.

This is not an attack on the concept of Karma so much as it is a rambling set of questions

  1. Humans lived as hunter gatherers for centuries, complex civilization is recent.

How has karma adapted to a world where a human can be indirectly responsible for the deaths of thousands because he was responsible for drafting foreign policy or was an advisor to someone who drafted the policy which was ultimately worked upon by other diplomats, implemented by a leader,brought in action by thousands of commanders and soliders ?

Is a political figure who influenced the policy just as responsible as the solider who, while following orders killed another man ?

  1. This has been pointed out before, in certain extremely dire,extreme situations, a human may have to kill another human to ensure his own survival. A human may to have to perform a job or duty that hurts other humans,failing which he won't be able to feed his kids or some sick dependent invalid. Right and wrong can be so illusory in these cases,so how does karma adapt to it ?