Foreign interventions in civil wars

"The policy implications of these results are fairly stark. If the objective of an intervention is to shorten the length of a civil conflict, then an outside military or economic intervention is not a terribly effective strategy to do so. Regardless of how the intervention is conceived – or empirically operationalized—there seems to be no mix of strategies that lead to shorter expected durations. Even maintaining a neutral posture or organizing the intervention under the auspices of a multilateral rubric is not sufficient to form an effective means of conflict management (p. 31)." (thanks Maria)