Quote from Anne Bowen Poulin,
"The power of nullification plays an important role in the criminal justice system. ... Because an accused criminal is restricted in the defenses he or she can raise, the law recognizes only certain defenses and justification, and correspondingly, limited evidence. The jury’s power to nullify provides an accommodation between the rigidity of the law and the need to hear and respond to positions that do not fit legal pigeonholes, such as claims of spousal abuse before the battered-spouse syndrome received acceptance. Jury nullification permits the jury to respond to a position that does not have the status of a legally recognized defense. The power to nullify guarantees that the jury is free to speak as the conscience of the community. "