There is general agreement in the literature that sustainable finance for universal social protection is attainable. Debate persists, however, on the most effective and most efficient measures to expand fiscal space to achieve universal protection. Strategies for domestic resource mobilisation and effective aid spending provide a wide range of options for national governments and donors to combine and sequence fiscal policies in ways that meet the unique economic, social and political conditions of different contexts. This paper briefly explores seven leading questions around the essential building blocks and foundation that would contribute to a sustainable fiscal space for social protection in the future.