The main objective of this study is to determine the impact of immigration interpreters on the testimony of Spanish-English bilingually conducted hearings in one U.S. immigration court. Specifically, I analyze the performance of nine immigration interpreters. I identify the precise linguistic strategies they employ when interpreting and, using conversational and other discourse analytical approaches, determine how they become active members of the proceedings. The immigration hearings I observed took place in one Federal immigration courtroom located in a large northeastern city. This research shows the extent to which interpreters play a pivotal role in controlling courtroom discourse—constructing courtroom reality and either mitigating or magnifying the culpability of defendants through a variety of linguistic mechanisms: a) inaccurate lexical choice, b) the use of source language rather than target language words and phrases, c) the use of definitions and calques, d) the improper addition or deletion of repair mechanisms and of hesitation forms such as pauses and fillers, and e) the addition of polite forms of address to convey solidarity, to adhere to Hispanic cultural norms, and to avoid face threatening acts. This study shows that the linguistic power interpreters wield exerts a coercive force, particularly on witnesses and defendants, and that such linguistic coerciveness on the part of interpreters influences other participants in the judicial proceeding. In this study, both judges and attorneys are shown to have been influenced by the lexical choices of interpreters. Finally, I show that the intrusiveness of interpreters changes the pragmatic force intended by the speakers, which constitutes a violation of the ethical standards set for interpreters in the United States by such authorities as the Federal Judicial Center.