Viral social media content has been heralded for its power to transform policy, but online responses are often derided as “slacktivism.” This raises the questions of what drives viral communications and what is their effect on support for social change. We addressed these issues in relation to Twitter discussions about Aylan Kurdi, a child refugee who died en route to the European Union. We developed a longitudinal paradigm to analyze 41,253 tweets posted 1 week before the images of Aylan Kurdi emerged, the week they emerged, and 10 weeks afterward—at the time of the Paris terror attacks. Tweeting about death before the images emerged predicted tweeting about Aylan Kurdi, and this, sustained by discussion of harm and threat, predicted the expression of solidarity with refugees 10 weeks later. Results suggest that processes of normative conflict and communication can be intertwined in promoting support for social change.