The purpose of this paper is to problematize evidence based approaches for understanding mundane teacher-student interaction by showing how education for democracy involves teachers’ handling of dilemmas between goals for promoting students’ personal engagement in controversial issues and to teach for critical thinking; further, I will argue that such knowledge is important for educating teachers to promote students development into a critical democratic participation. A case is taken from a Swedish religious studies classroom chosen from a larger classroom study about teacher student interaction in discussions about controversial issues. The case makes visible the dilemmatic praxis in which the teacher has to use her own judgment in order to promote a qualified democratic participation of the students, which also could be seen as an important part of teacher education. The visibility of such judgments however seems to be excluded in the discourse of evidence based teaching.