Abstract: What methods, what strategies, is it defensible for us to employ when campaigning on a contentious moral issue? What kinds of intolerance may we legitimately manifest towards the opposition in our endeavour to win converts and influence opinion? Could we be justified in refusing on principle even to engage with the opposition in public debate? And what of the legitimacy of ‘playing’ on people’s emotions, or of not correcting misinformation put about by some of our supporters which helps our cause? Or, in making use of premises in argument that our opponents accept but we do not or, of appealing to arguments that we know to be invalid but by which the opposition may be taken in?