How do disruptive events such as terrorism, disasters, and crises change public discourses? Do they alter journalistic distinctions between legitimate utterances and unacceptable viewpoints? This article provides answers to these questions through a unique data set concerning the coverage of immigration in Norway before and after the Oslo terror of 2011. The data serve as a natural experiment where we can analyze how immigration discourse was changed with regard to its magnitude, topical emphasis, and the sources interviewed. The analysis demonstrate that Hallin’s classic three-sphere model illuminates the dynamics of current meta-debates on polarized topics, where multiple online media continually criticize mainstream media and multiple voices question legitimate discourse. The main finding is that mainstream media definitions of appropriateness and deviance were challenged after the terror, as journalists adapted to a new political context. First, the issue of immigration was covered less in the months after the attacks. Second, the most vocal critics of the current immigration policies were put on the defensive, and debates with a critical potential were largely muted. At the same time, however, the attacks to some extent also opened mainstream media debate to online, deviant anti-Islamic actors who were previously largely silenced and ignored.