The fallacy of the single cause, also known as complex cause, causal oversimplification, causal reductionism, and reduction fallacy, is an informal fallacy of questionable cause that occurs when it is assumed that there is a single, simple cause of an outcome when in reality it may have been caused by a number of only jointly sufficient causes.
Fallacy of the single cause can be logically reduced to: "X caused Y; therefore, X was the only cause of Y" (although A,B,C...etc. also contributed to Y.)
Causal oversimplification is a specific kind of false dilemma where conjoint possibilities are ignored. In other words, the possible causes are assumed to be "A xor B xor C" when "A and B and C" or "A and B and not C" (etc.) are not taken into consideration; i.e. the "or" is not exclusive.
2. In a complex socio-political situation such as Yugoslavia, false simplification is not the best that can be done. It assures failure. The focus on Bosnia, for example, is an understandable mistake, since that is where most of the killing is occurring. It is an inadequate response since it comforts the illusion that the crisis can be resolved step by step, when, one way or another, all the people in the region are engaged in the complex, poisonous jumble of European history.