Allied states often seek to discourage other members from engaging in unnecessary conflicts, frequently working to mitigate and de-escalate tensions during crises involving their partners. This study investigates the de-escalatory influence of alliances − referred to as the restraint effect − on state behaviour during international crises. The central question addressed is: under what conditions does the restraint effect of alliances become more pronounced? The study hypothesizes that relatively weak states allied with major powers are more likely to experience a stronger restraint effect compared to others. This hypothesis is empirically tested using multiple regression models. The findings provide evidence of an additional restraint effect associated with the presence of a major ally within defence pacts. Furthermore, the temporal analysis reveals that this effect is particularly evident during the Cold War era.
