majority coalition can be stable, provided that reciprocity is sufficiently strong and widespread. In addition, a stable … minority coalition can exist, even with weak reciprocity preferences. This latter coalition is weakly larger than the maximum … stable coalition with standard preferences, but is characterized by mutually negative sentiments. …

on others' abatement. I show that a full or majority coalition can be stable. This requires, however, that a majority of … countries have relatively strong reciprocity preferences. No coalition participation is always stable. In addition, a stable … minority coalition may exist; if so, it is weakly larger than the maximum stable coalition with standard preferences, but is …