Commonwealth v. Aves: 1836

The Massachusetts court heard the case in a single, long day, from nine in the morning until seven at night, with practically no recesses. During the elaborate arguments, Loring and the other antislavery lawyers argued that slavery could not exist in Massachusetts unless the commonwealth expressly allowed it. Curtis and his co-counsel disagreed sharply. The federal Constitution clearly required the return of fugitive slaves who escaped to free states, they pointed out; thus a slave did not become free merely because he breathed the air of a free state. He told Shaw and his fellow jurists that what they thought, whether "as men or as moralists," was not at issue; only what the law said was moral mattered, and American law recognized slavery.

A unanimous court ruled against Aves a week later. Shaw first decided that Massachusetts had clearly abolished slavery, although he had great trouble pointing to exactly when and how it had done so. He proclaimed that "by the general and now well established law of this Commonwealth, bond slavery cannot exist, because it is contrary to natural right, and repugnant to numerous provisions of the constitution and laws." He then asked how far Massachusetts must go in respecting a slaveholder's property rights. Citing large numbers of English and American cases and commentators, he found that although the federal Constitution required a state to return a runaway slave to his or her owner, Med was not a runaway. Mary Slater had willingly brought her to Boston. Since Massachusetts was a free state, Shaw concluded, Slater could not exercise her property rights in a slave while there. He found that "all persons coming within the limits of a state, become subject to all its municipal laws, civil and criminal, and entitled to the privileges which those laws confer; … this rule applies as well to blacks as whites." The court thus barred Slater from taking Med back to Louisiana, ordering that Med be put into a guardian's custody instead. She was later adopted by Isaac Knapp, the publisher of the leading abolitionist newspaper The Liberator. Antislave forces had won an important battle.

Shaw's opinion in Commonwealth v. Ayes stands in sharp contrast to Thomas Ruffin's opinion in State v. Mann. The Mann opinion was short, clear, logical, and well-crafted. It also led to a result that hindsight reveals as immoral. In contrast, Shaw's Aves opinion was long and rambling, relying on hyper-technical legal discussion and poor logic, but it reached a more morally acceptable result, although Southern slaveholders disagreed. Together the two cases showed a widening gap in the courts and the constitutional system between what was legal and what was right, a gap that eventually became a civil war.