It is noted that communication scholars and teachers agree that the first step in joining a community is to learn the conventions of discourse of the target discipline. But argument in public policy arenas often involves multiple disciplines and must address ethical as well as technical issues. The authors term such discourse forums 'noncongruent sites' and explore the problem of how to determine when the field-specific discourse convections of specialists appropriately give way to ethical argument. It is argued that engineers must be educated to take a more than purely technical perspective on public issues. The curriculum at one institution is examined, and examples of courses and projects which tend to promote a broader perspective are given.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>