In the case of Sparf and Hansen v. United States in 1894, the U.S Supreme Court ruled that a trial judge has no responsibility to inform the jury of their right to nullify laws. This decision came after two seamen, John Sparf and Hans Peter Hansen were convicted for murdering a fellow sailor during an overseas voyage on an American vessel. The defense argued that they had been denied a fair trial because the judge refused to instruct jurors about their power to return a verdict against law if they believed justice required it - essentially arguing for jury nullification. However, Justice John Marshall Harlan delivered the majority opinion stating that while juries have de facto power of nullification due to double jeopardy protections (a defendant cannot be tried twice for the same crime), judges are under no obligation or even allowed by law to inform them about this potential authority.

In the dissenting opinion for Sparf and Hansen v. United States, Justice Brewer argued that juries should have the right to judge both the law and facts of a case, including determining what constitutes a crime. He believed this was essential in maintaining balance between government power and individual rights. Furthermore, he contended that it is not just about whether jurors have this right but also if they should be informed of it by judges during trials. He asserted that withholding such information from jurors could lead to unjust verdicts as they may blindly follow laws without considering their morality or fairness within specific contexts. This view stems from his belief in jury nullification - where juries can acquit defendants even when evidence clearly shows them guilty under an unfair law - which he saw as an important safeguard against tyranny.