Jury nullification is a de facto power of juries. Judges rarely inform juries of their nullification power. The power of jury nullification derives from an inherent quality of most modern common law systems—a general unwillingness to inquire into jurors' motivations during or after deliberations. A jury's ability to nullify the law is further supported by two common law precedents: the prohibition on punishing jury members for their verdict, and the prohibition (in some countries) on retrying defendants after an acquittal (see related topics res judicata and double jeopardy).
We, the people, have the ability, and the duty, to make a change in courtrooms as well as with our legislators. Unfortunately, most of the people are unaware of their power as jurors.
I haven't lost my mind -- it's backed up on tape somewhere.