Ever-increasing numbers of teachers are expressing commitments to social justice education today, but few experienced critical or democratic education in their own schooling or in their teaching practicum. Thus, teachers’ critical democratic commitments can be difficult to put into practice, especially in classrooms where students with diverse and unequal positionalities are engaged in learning together – what I call “heterogeneous” classrooms. Education that is “democratic” (that includes a range of warranted perspectives) can seem to come into conflict with education that (...) is “critical” (that elevates and centers marginalized perspectives). We have little research depicting how educators meet such challenges. This paper depicts an experienced and committed social justice educator wrestling with difficult problems in the enactment of critical democratic education. Mr. Crane regularly engaged his racially and linguistically heterogeneous students in discussions of social issues, and during these discussions regularly encountered practical facilitation challenges posed by inequality among students. He wrestled with how to elevate students of color's views without spotlighting them, and how to challenge dominant perspectives without shaming the students who voiced them. Drawing on qualitative data from classroom observations and interviews, I depict Mr. Crane making sense of and mobilizing emergent instructional responses to these challenges – with, by his own reckoning, mixed results. One instructional routine, an impromptu version of a critical inquiry, was flagged by Mr. Crane as a promising method for navigating some of the trickiest problems of critical democratic education practice. This paper's findings demonstrate that enacting critical democratic education is not easy. Even experienced and committed social justice educators struggle with how to put their critical values into practice. By making visible one experienced critical democratic educator's recurring problems of practice, my research acknowledges the difficulties of this work and contributes to problem-framing. Furthermore, by deconstructing a promising routine for impromptu critical inquiry during classroom discussions of social issues, this research contributes a model of effective critical democratic education in practice. (shrink)