There are several important principles involved in this case, which have been argued, and which may be considered under the following heads:
1. The locality of slavery, as settled by this court and the courts of the States.
2. The relation which the Federal Government bears to slavery in the States.
3. The power of Congress to establish Territorial Governments, and to prohibit the introduction of slavery therein.
4. The effect of taking slaves into a new State or Territory, and so holding them, where slavery is prohibited.
5. Whether the return of a slave under the control of his master, after being entitled to his freedom, reduces him to his former condition.
6. Are the decisions of the Supreme Court of Missouri, on the questions before us, binding on this court, within the rule adopted.
In the course of my judicial duties, I have had occasion to consider and decide several of the above points.
1. As to the locality of slavery. The civil law throughout the Continent of Europe, it is believed, without an exception, is, that slavery can exist only within the territory where it is established; and that, if a slave escapes, or is carried beyond such territory, his master cannot reclaim him, unless by virtue of some express stipulation. (Grotius, lib. 2, chap. 15, 5, 1; lib. 10, chap. 10, 2, 1; Wicqueposts Ambassador, lib. 1, p. 418; 4 Martin, 385; Case of the Creole in the House of Lords, 1842; 1 Phillimore on International Law, 316, 335.)
There is no nation in Europe which considers itself bound to return to his master a fugitive slave, under the civil law or the law of nations. On the contrary, the slave is held to be free where there is no treaty obligation, or compact in some other form, to return him to his master. The Roman law did not allow freedom to be sold. An ambassador or any other public functionary could not take a slave to France, Spain, or any other country of Europe, without emancipating him. A number of slaves escaped from a Florida plantation, and were received on board of ship by Admiral Cochrane; by the King's Bench, they were held to be free. (2 Barn. and Cres., 440.)