The public perception of court interpreters operates through theories located in discourses both within and around the court. Analysis of interpreting at the 1995 criminal trial of O. J. Simpson shows that such theories are able to explain apparent linguistic shifts in terms of lexical non-correspondence, intralingual discursive coherence, sociocultural bias, variety alignment, a 'user-expectation' principle, the fiction of non-hermeneutic rendition as a mode of professional demarcation, the priority of the cultural component, and various appeals to linguistic and academic expertise. Although all these approaches can provide explanations of apparent shifts, only cost-beneficial theories are found to be successful within the court context. It is concluded that any scholarly intervention in this field should be in terms of theories able to provide explanations adequate to the amount of analytical effort to be invested.