Moral responsibility is a prominent concept used in political discourses and theoretical debates. Yet disagreement remains on how it could work in practice. When attempting to address global challenges such as global poverty, combating atrocities, or artificial intelligence, approaches often revert to retrospective accounts of responsibility that focus on non-compliance with regulatory frameworks. As a result, cases where prospective responsibility would be required often go unaddressed. In this article, we introduce an analytical conceptualization of responsibility that should help to guide the application of moral responsibility in such situations. In the first step, we develop a typology that distinguishes between four types of responsibility: ‘obligatory’, ‘structural’, ‘prescribed’, and ‘discursive’. Second, we identify responsibility gaps for each responsibility type. Third, we introduce different ethical principles from political theory that help to identify potential responsibility relations. We illustrate the utility of this framework with the example of climate change, where ethical principles beyond the contribution principle have already been applied. The paper facilitates new perspectives in political debates about how to allocate responsibility in light of global challenges and enhances theoretical debates in International Relations scholarship.