The following article traces the tactical co-development as a process within ‘mutual brokerage’ between Anglo-American abolitionists. In the case of the Anglo-American abolitionist network of the early nineteenth century, the co-production of so-called ‘world conventions’ brought together an international network of abolitionist actors tied to one another through previous fora for discussion and debate. Mutual brokerage is perhaps most clearly seen within the example of female abolitionists during the nineteenth-century abolition campaigns. Women brought to the Anglo-American abolitionism the co-development of tactics through writings, planning, meetings, speeches, and petition writing. The article argues for a dialogical account regarding the spread of ideas and a reexamination of the role of brokerage within tactical diffusion. The writings and in-person debate about the ethical and moral concerns of the movement were channels through which ideas flowed. Instead of a one-directional flow with brokers as translators bringing new tactics from one locale to another, the channels were characterized by the absence of earlier ‘originators’ and later ‘adopters’ – traditional categories assigned to actors within the diffusion process. Rather, the article posits that the channels of transmission shaped the spread of ideas and subverted the traditional categories of ‘transmitters’ and ‘receivers’ found in more monological accounts of diffusion.