The first Arithmetic operation that we all learn is summing things…
So when we come to evaluate a person or a movement we are looking for the ‘pros’ and ‘cons’ and try to sum up. If the virtues outweigh the vices we would consider the sum to be positive.
But this seems to me too simplistic.
If some party is a central Socialist force but also very Repressive, if someone is a great Anti Imperialist leader and also a Big Thief, the combination is not linear. Socialist governments that alienate their people tend to undermine socialism. The big thieves under the banner of anti imperialism are opening all the doors for local collapse and foreign intervention. Somehow I would prefer, in most cases, to have the Kleptomaniacs and the Sadists clearly on the other side.
Let me suggest another type of Arithmetics for such cases: Multiply the virtue by the vice – the result will depend on the size of both but will always be negative. The more virtues you have your crimes are more destructive.