Fault (cf. contribution)
Fault is used to assign blame. I use it as synonymous with the word blame. It also focuses on one factor or agent as the one at fault (to the exclusion of other contributing factors).
Faulting/blaming is the major factor that contributes to the the start of and continuing of disagreements between people and peoples. For example, a husband blames/faults his wife in a dispute. He singles out her behavior(s) as the cause of the disagreement, while neglecting to notice or get curious out how his behavior(s) may be contributing to the disagreement. His wife is doing the same, except turned around the other way.
In contrast, I use the word "contribution" to indicate that one person, group of people, or other factor(s), out of several, was instrumental in creating a given outcome (whether considered desirable or undesirable).
Fault is only used regarding outcomes that are considered to undesirable.