The actual costs of Thabo Mbeki's AIDS denialism are probably incalculable. Nonetheless, a recent Harvard University study gives at least some indication of the consequences of the very real damage he did on this issue. According to the study, access to retrovirals and other drugs likely would have prevented the premature deaths of 365,000 people. This will go down as Thabo Mbeki's greatest failing as a leader, indeed as the only nearly unforgivable shortcoming of his tumultuous presidency.