Do Alliances Deter Aggression? The Influence of Military Alliances on the Initiation of Militarized Interstate Disputes

Point: Alliances do influence the probability of MIDs but the direction of that influence depends on the content of the treaty.
The article argues that we should disaggregate the alliances depending on their content rather than considering all of them alike.
We can distinguish five different basic promises included in alliances:
1.Defensive cooperation,
2.Offensive cooperation, 
4.Non-aggression, and
Alliance treaties often include precise language identifying specific conditions under which different promises come into effect.
Challengers, who have commitments from allies to cooperate offensively or to remain neutral in the event of conflict with the potential target, are more likely to initiate disputes than those without such allies.
Relative defense pacts can deter aggressors from attacking alliance members, but relevant offense pacts and neutrality commitments can provide the assurance that aggressor need to facilitate attack.