"Do I have the right?"

The Doctor has been sent to Skaro's past by the Time Lords, who want him to prevent (or at least severely weaken) the creation of the Daleks, a species infamous for their violent authoritarianism and genocidal racism. When presented with an opportunity to wipe out the Daleks in one blow, however, the Doctor is deeply conflicted on the matter, both because of how many worlds will unite against the Daleks and out of fear of becoming no different than them by committing genocide.

Example of:
Genocide Dilemma