In the case of Sebastian Willot, John McDonald, and Joseph Hunn v. John F. A. Sandford, the plaintiffs in error argued that they were illegally held as slaves by Sandford while living in Illinois - a free state at the time - and thus should be freed from their servitude. The Supreme Court ultimately ruled against them on grounds that even though they had been brought to Illinois involuntarily from Missouri (a slave-holding state), they still did not have legal standing under federal law to sue for freedom because of their status as slaves prior to entering Illinois; this was due to an 1820 act which stated that any person who entered a free state with intent to remain there could not use such residence as a basis for suing for freedom unless it was done through proper channels established by Congress or other legislative bodies within each respective state.

In the case of Sebastian Willot, John McDonald, and Joseph Hunn v. John F. A. Sandford, the dissenting opinion argued that the court should have found in favor of the plaintiffs due to their right to freedom as protected by a prior act of Congress from 1820 which abolished slavery in Missouri Territory. The majority opinion had ruled against them on technical grounds related to how they were brought into court and whether or not they could be considered citizens under state law at that time; however, Justice Curtis argued that this was irrelevant because it did not address their fundamental rights as free persons under federal law. He further stated that since no other legal remedy existed for these individuals who had been wrongfully enslaved despite being legally freed by an act of Congress years earlier, then justice demanded a ruling in their favor regardless of any procedural issues with bringing suit before the court.