This article offers a linguistic analysis of interpersonal stancetaking in four argumentative term papers written in an upper-level undergraduate course in economics. Two of the papers were written by English L2 writers who experienced particular difficulty with the assignment and two by English L1 writers who received the highest grades among the forty students in the course. My analysis is guided by the question of how recurring patterns of interpersonal meanings operate to construct an argumentative stance that indexes, or not, the specific goals and expectations for writing in the course. Considered alongside interviews with the professor and the graduate student instructor (GSI) who graded and commented on the papers, my analysis draws on the "Engagement" framework from systemic functional linguistics (Martin & White, 2005), which has proven useful in recent years for understanding the ways both professional and student writers (Chang & Schleppegrell, 2011; Derewianka, 2009; Wu, 2007) use language to construct an authorial stance within specific disciplinary contexts. Following my analysis, I consider implications of this line of research for working with English L2 writers in upper-level courses in the disciplines.