This paper addresses the electoral consequences of the German government’s anti-nuclear power policy shift after the Fukushima accident. Building on a cost-benefit framework and insights from political psychology, the theoretical analysis anticipates that the policy shift could not earn governing parties additional votes but could avoid vote loss. Utilizing data from multiple surveys and employing simulation techniques, the evidence demonstrates that voters, in particular incumbents’ supporters, became more skeptical of nuclear power after the Fukushima disaster. At the same time, governing parties’ supporters were particularly eager to perceive a credible change in the government’s nuclear power stance. As a consequence, governing parties did not garner additional votes but inhibited their supporters from voting for other parties and thus avoided vote loss. Generally speaking, the novel approach proposed in this paper is suitable for shedding light on electoral effects of parties’ policy shifts that have thus far gone unnoticed.