This paper is a slightly expanded version of a keynote address I delivered a month ago at an international conference on argumentation in Tokyo. The first half constructs an etymological history of the terms "forensic" and "forensics" in order to make the point that the confusion among the different senses of the terms reflects key differences among Western argument practices within legal institutions. This sets aside the ordinary view within communication studies that "forensic" is a genre category that is specific to legal discourses. The second half comments on the involvement of American "democracy promoters" (law professors and consultants) in the implementation of the saiban-in, or quasi-jury system for adjudication of serious criminal offenses in Japan. It suggests that argument studies that recognize the complexities that "forensic advocacy" bring to legal communication can be helpful both in understanding how transnational diffusion of innovations produces sites of controversy and in inspiring practitioners to be more reflective of the cultural diversity embedded in their own traditions.