This article provides a comparative case study of the development of identity distinctions between two peace movement organizations during the Persian Gulf crisis. Distinctions between these two SMOs' identities are traced through their collective action frames and through self evaluative framing. It is found that the identities are related to the SMOs' organizational structures, their career stages, and their desired positions in relation to the ''mainstream'' and past movement identities. Implications for effectiveness of such identity making is considered.