The Covid pandemic pushes us all to reflect on the idea of a just society. The theories of the great Harvard philosopher John Rawls - from his "veil of ignorance" to his "difference principle" - can play a vital and inspiring role in helping us to understand and bring about justice. Yet, as MP and Financial Secretary to the Treasury Jesse Norman shows, Covid also raises unsettling questions for Rawls's own thought, and for what a just society actually looks like.