3-20. Peace operations require opposing parties to cooperate with the international community, including international organizations and nongovernmental organizations. In most peace operations, this cooperation is voluntary. However, peace enforcement involves the threat or use of military force to compel cooperation. Consolidation of gains and its associated stability operations will be required. The likelihood of combat declines, and, when it occurs, it is usually at the small-unit level. Military forces involved in peace operations prepare for sudden engagements even while executing operations to prevent them.