## Facts

- A six-year-old girl, Med, was held as an enslaved person under Louisiana law and treated as the property of Samuel Slater, a Louisiana citizen.
- Mary Slater, visiting Boston from Louisiana, brought Med as a personal attendant and left her in the Boston household of her father, Thomas Aves, during Mary’s illness.
- An abolitionist resident filed a petition for a writ of habeas corpus alleging Med was unlawfully restrained by Aves.
- Aves admitted custody and justified detention on the ground that Med was a slave under Louisiana law and was intended to be returned to Louisiana after the temporary visit.
- The case was heard by the Massachusetts Supreme Judicial Court on the habeas petition.

## Issues

1. Whether Massachusetts must recognize and enforce a slaveholder’s claimed property right in a person brought voluntarily into Massachusetts for a temporary visit from a slave state.
2. Whether the U.S. Constitution’s fugitive-slave provision requires Massachusetts to permit detention and removal of a person who was not a fugitive but was brought into the state by the purported owner or agent.
3. Whether interstate comity obligates Massachusetts to give effect to Louisiana’s slavery laws despite Massachusetts’s prohibition of slavery.

## Decision

- The court granted habeas relief and ordered Med released from Aves’s custody.
- The court held that a visitor from a slave state who brings an enslaved person into Massachusetts temporarily cannot restrain that person’s liberty while in Massachusetts or remove the person from Massachusetts against her consent.
- The court concluded that slavery could not exist under Massachusetts law and that any claimed master’s right depended on foreign law with no force in Massachusetts.
- The court held the constitutional duty to return fugitive slaves did not apply because Med was not a fugitive.
- Med was treated as free in Massachusetts and placed under a court-appointed guardian.

## Legal Principles

- Slavery is a status that exists only by positive local law; it has no legal effect in a jurisdiction whose law does not recognize it.
- Persons within Massachusetts are subject to Massachusetts municipal law and entitled to its protections without racial distinction.
- The constitutional fugitive-slave provision creates a limited exception requiring return only of persons who escape from service; it does not compel recognition of slavery for persons voluntarily brought into a free state.
- Interstate comity is discretionary and may be refused where enforcement of foreign law would conflict with the forum state’s fundamental policy, including its rejection of slavery.
- A claimed property right in a person, grounded solely in the law of another state, cannot justify detention in Massachusetts where slavery is unlawful.

## Conclusion

Massachusetts held that slavery’s legal force is territorial: an enslaved child brought voluntarily into Massachusetts during a temporary visit could not be lawfully restrained or carried out of the state against her will, because Massachusetts did not recognize slavery and neither the Constitution’s fugitive-slave clause nor comity required enforcement of Louisiana’s slave law.


Commonwealth v. Aves, 35 Mass. (18 Pick.) 193 (1836)