The competition for power in a complex social world is hypothesized to be a driving force in the evolution of intelligence 1. More specifically, power may be obtained not only by brute force but also by social strategies resembling human politics 2. Most empirical evidence comes from primate studies that report unprovoked aggression by dominants to maintain power by spreading fear 3 and third-party interventions in conflicts 4–6. Coalitionary support has also been described in other animals 7, 8 and is often linked to social bonding 9, 10. As coalitions can lead to a gain in power 5, 11 and fitness benefits 12, individuals may try to prevent coalitionary support or indirectly prevent others from forming social bonds that might lead to coalitions. Although there is some empirical evidence that coalitionary support can be manipulated 13, little is known about the indirect strategy. We show here that wild ravens (Corvus corax) regularly intervene in affiliative interactions of others even though such interventions are potentially risky and without immediate benefits. Moreover, the identities of both interveners and intervened pairs are not randomly distributed. Ravens with existing ties initiate most interventions, and ravens that are creating new ties are most likely to be the targets of interventions. These patterns are consistent with the idea that interventions function to prevent others from forming alliances and consequently becoming future competitors. We thus show previously undescribed social maneuvers in the struggle for power. These maneuvers are likely to be of importance in other social species as well. •Ravens regularly engage in risky interventions in others’ affiliative encounters•Strongly bonded birds are more likely to intervene in affiliative interactions•Interventions almost exclusively target pairs that attempt to form new bonds•Ravens may prevent others from forming alliances and becoming future competitors Animals can gain and maintain power by force, but also through support from social allies. Massen et al. show that ravens with established allies selectively intervene in bonding attempts of other ravens, suggesting that they try to prevent those from forming alliances. Such a “divide and rule” strategy has not been hitherto described for birds.