We explore whether there is a plausible probabilistic version of the Doctrine of Double Effect (DDE), and more generally pursue the question of how probabilistic outcomes affect the application of moral principles. Many think that the DDE helps explain why it is permissible to shunt a trolley onto a sidetrack to which one person is tied (thereby resulting in his death) in order to save the lives of five people tied to the main track, whereas it is impermissible to lead an unsuspecting person onto the main track in order to save the five. But we can ask: Does it make a difference if we have an option to lead a person onto the main track when there is only a small to moderate chance that he will be killed? Here we make a start toward an answer by investigating why it is generally wrong to risk harm to others, taking as a defeasible starting point a pluralistic deontological account of morality. In the process, we explore whether imposing risk is causing harm, how to sort permissible from impermissible risk impositions, and why we should not expect a linear function between degree of risk imposed and seriousness of wrong.