The big issue I see with nullification is that, once you grant it is justified unjust laws, you make it so that any law can be nullified in a given case, depending on the particular jury selected.
Good! you might say. But now imagine you're in the rural South, trying a case of what was effectively a lynching. If you say that jurors can ignore the facts of the case and the law, no matter how much evidence you offer that a particular person is a murderer, they can ignore it for white supremacy.
This is on top of issues about fairness and equal application of the law. Whether and how much you're punished would vary even more depending on the makeup of the jury, even if the crime is the exact same.
Good! you might say. But now imagine you're in the rural South, trying a case of what was effectively a lynching. If you say that jurors can ignore the facts of the case and the law, no matter how much evidence you offer that a particular person is a murderer, they can ignore it for white supremacy.
This is on top of issues about fairness and equal application of the law. Whether and how much you're punished would vary even more depending on the makeup of the jury, even if the crime is the exact same.