The Common Core State Standards (CCSS) explicitly call for a wide variety of writing assignments in all subjects, with special emphasis on informational writing and argumentation (National Governors Association). In a footnote to the 6-12 writing standards, the CCSS point out that "these broad types of writing include many subgenres" (English 41), yet the importance of genre is never explored. Instead, all informational and argumentative genres are treated equally; the standards implicitly suggest that students will benefit in similar ways from a well-designed assignment in any informational or argumentative genre. Through a case study reported here, the author argues that this is not necessarily the case. Deliberately selecting a specific genre and teaching it authentically can result in genre-specific student learning that goes significantly beyond the written product or even the writing itself. However, to engage students in writing most effectively, educators must design writing activities that exhibit not just what the author calls "latent authenticity," but "functional authenticity."