The balance of power theory in international relations suggests that national security is enhanced when military capability is distributed so that no one state is strong enough to dominate all others. If one state becomes much stronger than others, the theory predicts that it will take advantage of its strength and attack weaker neighbors, thereby providing an incentive for those threatened to unite in a defensive coalition. Some realists maintain that this would be more stable as aggression would appear unattractive and would be averted if there was of power between the rival coalitions.