In these fraught, divisive times, K-12 educators have an opportunity to make a profound contribution to students' academic, intellectual, and civic maturity by giving civil, purposeful discussion the priority it deserves. With reading and writing, discussion is a co-equal leg of the tripod of literacy. By engaging in frequent discussions of challenging academic content, students could learn to listen (not just wait for their chance to talk), to offer their thoughts with an open mind, to fairly consider multiple perspectives, and to agree to respectfully disagree. They could carry these vital abilities with them into adulthood, which would prepare them to become more contributive citizens, better neighbors, and more productive employees. In fact, employers rank communication and interactional acumen among their highest priorities. This article makes the case for civil, rational argument in the classroom, describes how any teacher can conduct such discussions, and highlights schools where these discussions have led to both high engagement and significant academic gains.