"We have been here when MLE Chief Barty Crouch insisted that permitting Aurors to use Unforgivables was necessary to stop the Death Eaters at the end of the previous war in 1980, and again by Minister Scrimgeour in this more recent conflict. We're still finding sleeper citizens getting triggered under a latent Imperious Curse, confused as they are trying to attack and arrest or kill someone. Beyond that, in order to "make us feel safe', Scrimgeour threw innocent people like Stan Shuntpike in Azkaban.