Potential loss of group distinctiveness can represent a threat to the existence of a group. Across three studies (Ns = 42, 60, 94), a mediated-moderation model was tested in which the interactive effects of group identification and potential ingroup distinctiveness loss predicts the desire to engage in ingroup protective action to the extent that collective angst (i.e., concern for the ingroup's future vitality) is aroused. It was hypothesized that the threat of potential distinctiveness loss would result in collective angst and subsequent support for protective action among high, but not necessarily low, identified group members. Results provided support for this model within the context of French Canadian distinctiveness from English Canada (Experiment 1, where the outcome measure was the desire for a sovereign Quebec) and Canadian distinctiveness from the United States (Experiments 2 and 3, where the outcome was support for action to protect Canadian sovereignty and rejection of a North American Union respectively). When and why collective angst facilitates ingroup protective action is discussed. Copyright © 2010 John Wiley & Sons, Ltd.