65. Enforcement of the Supplementary Acts, 1818-1825. A somewhat more sincere and determined effort to enforce the slave-trade laws now followed; and yet it is a significant fact that not until Lincoln’s administration did a slave-trader suffer death for violating the laws of the United States.  The participation of Americans in the trade continued, declining somewhat between 1825 and 1830, and then reviving, until it reached its highest activity between 1840 and 1860.  The development of a vast internal slave-trade, and the consequent rise in the South of vested interests strongly opposed to slave smuggling, led to a falling off in the illicit introduction of Negroes after 1825, until the fifties; nevertheless, smuggling never entirely ceased, and large numbers were thus added to the plantations of the Gulf States.

Monroe had various constitutional scruples as to the execution of the Act of 1819;[124] but, as Congress took no action, he at last put a fair interpretation on his powers, and appointed Samuel Bacon as an agent in Africa to form a settlement for recaptured Africans.  Gradually the agency thus formed became merged with that of the Colonization Society on Cape Mesurado; and from this union Liberia was finally evolved.[125]

Meantime, during the years 1818 to 1820, the activity of the slave-traders was prodigious.  General James Tallmadge declared in the House, February 15, 1819:  “Our laws are already highly penal against their introduction, and yet, it is a well known fact, that about fourteen thousand slaves have been brought into our country this last year."[126] In the same year Middleton of South Carolina and Wright of Virginia estimated illicit introduction at 13,000 and 15,000 respectively.[127] Judge Story, in charging a jury, took occasion to say:  “We have but too many proofs from unquestionable sources, that it [the slave-trade] is still carried on with all the implacable rapacity of former times.  Avarice has grown more subtle in its evasions, and watches and seizes its prey with an appetite quickened rather than suppressed by its guilty vigils.  American citizens are steeped to their very mouths (I can hardly use too bold a figure) in this stream of iniquity."[128] The following year, 1820, brought some significant statements from various members of Congress.  Said Smith of South Carolina:  “Pharaoh was, for his temerity, drowned in the Red Sea, in pursuing them [the Israelites] contrary to God’s express will; but our Northern friends have not been afraid even of that, in their zeal to furnish the Southern States with Africans.  They are better seamen than Pharaoh, and calculate by that means to elude the vigilance of Heaven; which they seem to disregard, if they can but elude the violated laws of their country."[129] As late as May he saw little hope of suppressing the traffic.[130] Sergeant of Pennsylvania declared:  “It is notorious that, in spite of the utmost vigilance that can be employed, African negroes are