I outline four conditions on permissible promise-making: the promise must be for a morally permissible end, must not be deceptive, must be in good faith, and must involve a realistic assessment of oneself. I then address whether promises that you are uncertain you can keep can meet these four criteria, with a focus on campaign promises as an illustrative example. I argue that uncertain promises can meet the first two criteria, but that whether they can meet the second two depends (...) on the source of the promisor's uncertainty. External uncertainty stemming from outside factors is unproblematic, but internal uncertainty stemming from the promisor's doubts about her own strength leads to promises that are in bad faith or unrealistic. I conclude that campaign promises are often subject to internal uncertainty and are therefore morally impermissible to make, all else being equal. (shrink)