US Presidency
1859

In that event any one State could have effectually continued the trade, not only for itself, but for all the other slave States, though never so much against their will. And why? Because African slaves, when once brought within the limits of any one State in accordance with its laws, can not practically be excluded from any State where slavery exists. And even if all the States had separately passed laws prohibiting the importation of slaves, these laws would have failed of effect for want of a naval force to capture the slavers and to guard the coast. Such a force no State can employ in time of peace without the consent of Congress. These acts of Congress, it is believed, have, with very rare and insignificant exceptions, accomplished their purpose. For a period of more than half a century there has been no perceptible addition to the number of our domestic slaves. During this period their advancement in civilization has far surpassed that of any other portion of the African race.