When someone has visited a bar to have a few drinks before making the dangerous decision to drive home, any accident they cause as a result of negligence will be their fault. They made the initial choice to go for a drink and then drive home afterwards, as opposed to catching a taxi or getting a friend to come and pick them up. Therefore, in any legal case involving such circumstances, the drunk driver is almost always at fault; they made an ill-thought-out choice and must face the consequences after sobering up and coming to terms with the damage they have done.
But what about those who have inadvertently caused an accident because they suffer from a mental illness? What if someone who is not in total control of their intellectual faculties fails to understand that they did something morally wrong? For example, in many mass shootings across the U.S. in recent years, the perpetrators have almost universally suffered from some kind of mental illness and chosen to plea insanity, including James Eagan Holmes, the perpetrator of the 2012 shooting in an Aurora theater.