"That a treaty with a foreign nation cannot deprive Congress of any part of its legislative power conferred by the people, so that it no longer can legislate as it is empowered by the Constitution."
Also, that if the treaty expressly prohibited (as it did not) the exclusion of slavery from the ceded territory the "court could not declare that an act of Congress excluding it was void by force of the treaty. . . . A refusal to execute such a stipulation would not be a judicial, but a political and legislative question. . . . It would belong to diplomacy and legislation, and not to the administration of existing laws."(36)
Plainly no part of the treaty of cession fastened slavery, or any other institution of France, on the territory ceded to the United States. If its provisions were violated by the United States, France, internationally, or the inhabitants at the date of the treaty, might have complained and had redress. Obviously the treaty had no bearing on the question of slavery in the United States, but its provisions were seized upon, as was every possible pretext, by the votaries of slavery to maintain and extend it.
It was also, by a majority of the court, held in this memorable case (hereafter to be mentioned) that under the third article of the cession slaves could be taken from any State into any part of the Louisiana Purchase during its territorial state, and there held, and hence that the Missouri Compromise, of 1820, forbidding slavery in the territory north of 36° 30´, was in violation of the treaty and was unconstitutional, as were all other acts of Congress excluding slavery from United States territory. This was in the heyday (1857) of the slave power, and when it aspired, practically, to make slavery national.
This aggressive policy, as we shall see when we come to consider the Nebraska Act of 1854 relating to a principal part of the Louisiana Purchase, led to a great uprising of the friends of freedom, the political overthrow of the advocates of slavery in most branches of the Union; then to secession; then to war, whence came, with peace, universal freedom, and slavery in the Republic forever dead.
(35) For map showing territory acquired by the U. S., by each treaty, etc., see History Ready Ref., vol. v., p. 3286, and Louisiana Purchase (Hermann, Com. Gen. Land Office). The original thirteen States and Territories comprised 8,927,844 sq. mi. The Louisiana Purchase, 1,171,931, sq. mi.
(36) Dred Scott Case, 19 Howard, 393, etc.
XI FLORIDA
Florida did not become a slave colony even on being taken possession of by the English in 1763, nor on its re-conquest by Spain in 1781.
By the treaty of peace at the end of the war of the Revolution (1783) Great Britain recognized as part of the southern boundary of the United States a line due east from the Mississippi at 31° of latitude; and at the same time, by a separate treaty, she ceded to Spain the then two Floridas. Florida became a refuge for fugitive slaves from Georgia and South Carolina.