Buddhism explains karma in order to reveal how to transform it. Put another way, to hold the doctrine of karma over people without fully clarifying the means for changing it is to wrongly interpret Buddhism. Such teachings only cause people to remain bound by the shackles of fate.
Present effects are due to karmic causes from the past. However, future effects arise from the causes we make in the present. It is always the present that counts. It is what we do in the present moment that decides our future; our past causes do not govern our future as well. Nichiren Buddhism emphasizes that no matter what kind of karmic causes we have made in the past, through the causes we make in the present we can achieve a brilliant future.