In my opinion Politics especially, that cause damage to the society are dirtier,

Politics in any field is like a parasite. It eats up a person, organization or country from the inside. Though it is a necessary evil in the case of a country, it still has a repulsive feel to it.

We have become kind of accustomed with national politics. No matter how filthy the fight for power gets, we are not surprised. I think family politics is a lot worse as you don't expect your own people to plot against you.

Caste based, religion based, region based, family based politics are definitely narrow and undesirable. The family oriented politics is most narrow and thus worst.  

Politics of any kind is a big problem. It becomes a matter of worry. Though we all know, national politics is full of undesirable activities still, I would say family politics is the worst of the lot. Our own blood plotting against each other is literally a disgraceful act.Politics is an unfair game but politics should not exist within a family if it does so then it's a murder of an institution called family.