Your believing or not believing in karma has no effect on its existence, nor on its consequences to you. Just as a refusal to believe in the ocean would not prevent you from drowning.
When the time is up for maturation of karma, it automatically comes into effect.
Karma is a universal law of cause and effect. You reap what you sow.
The reality is that international institutions like the UN can only be as effective as its members allow it to be.
If you want to know your true opinion of someone, watch the effect produced in you by the first sight of a letter from him.