octrine was
subsequently modified by another English chief-justice, Lord Stowell,
in 1827, to the effect that absence of positive law to support slavery
in England only operates to suspend the master's authority, which is
revived if the slave voluntarily returns into an English colony where
slavery does exist by positive law.

The States of the Union naturally inherited and retained the common
law of England, and the principles and maxims of English jurisprudence
not necessarily abrogated by the change of government, and among
others this doctrine of Lord Mansfield. Unlike England, however, where
there was no slavery and no law for or against it, some of the
American States had positive laws establishing slavery, others
positive laws prohibiting it. Lord Mansfield's doctrine, therefore,
enlarged and strengthened by American statutes and decisions, had come
to be substantially this: Slavery, being contrary to natural right,
exists only by virtue of local law; if the master takes his slave for
permanent residence into a jurisdiction where slavery is prohibited,
the slave thereby acquires a right to his freedom everywhere. On the
other hand, Lord Stowell's doctrine was similarly enlarged and
strengthened so as to allow the master right of transit and temporary
sojourn in free-States and Territories without suspension or
forfeiture of his authority over his slave. Under the complex American
system of government, in which the Federal Union and the several
States each claim sovereignty and independent action within certain
limitations, it became the theory and practice that towards each other
the several States occupied the attitude of foreign nations, which
relation was governed by international law, and that the principle of
comity alone controlled the recognition and enforcement by any State
of the law of any other State. Under this theory, the courts of slave
States had generally accorded freedom to slaves, even when acquired by
the laws of a free-State, and reciprocally the courts of free-States
had enforced the master's right to his slave where that right depended
on the laws of a slave-State. In this spirit, and conforming to this
established usage, the local court of Missouri declared Dred Scott and
his family free.

The claimant, loath to lose these four human "chattels," carried the
case to the Supreme Court of the State of Missouri, where at its March
term, 1852, it was reversed, and a decree rendered that these