Several implications follow. First, hegemonic leadership is more likely in
bipolarity, because the asymmetry of power between leaders and clients will be
greater and because the bipolar rivalry gives the two leading states additional
incentives to keep their allies in line.28
Second, hegemonic leadership is most
likely when the alliance leader has extensive global interests and faces a seriousexternal threat, because this creates both a desire for allied support and an
incentive to acquire influence over other states. Third, hegemonic leadership is
most easily exercised against relatively weak clients, which means that this tactic
will be most effective for preserving alliance ties that are relatively less
valuable.29
Finally, hegemonic leadership is not a permanent solution to strong
centrifugal tendencies. Not only will major external changes affect the leader's
interests - and thus its willingness to pay a disproportionate share of the alliance
costs - but the additional burdens of alliance leadership will eventually erode the
asymmetry of power on which such leadership depends