Around the world, citizens are voting away the democracies they claim to cherish. Why are they voting against their own values? In this article, we provide evidence that this behavior is driven in part by fear that their opponents might dismantle democracy first. In an observational study (N=1,973), we find that US partisans who most fear the other party’s willingness to subvert democracy are also those most willing to support subverting democracy themselves. In experimental studies (N=2,543, N=1,848), we use an intervention to reduce these often exaggerated fears. With these fears reduced, partisans become more committed to upholding democratic norms. They may also become more willing to vote against candidates of their own party who break these norms. The findings suggest that we can foster democratic stability by strengthening trust in opposing partisans’ commitment to democracy.