and under special circumstances.  A failure of any one nation to do one of these two things meant that the efforts of all other nations were to be fruitless.  The United States had invited the world to join her in denouncing the slave-trade as piracy; yet, when such a pirate was waylaid by an English vessel, the United States complained or demanded reparation.  The only answer which this country for years returned to the long-continued exposures of American slave-traders and of the fraudulent use of the American flag, was a recital of cases where Great Britain had gone beyond her legal powers in her attempt to suppress the slave-trade.[52] In the face of overwhelming evidence to the contrary, Secretary of State Forsyth declared, in 1840, that the duty of the United States in the matter of the slave-trade “has been faithfully performed, and if the traffic still exists as a disgrace to humanity, it is to be imputed to nations with whom Her Majesty’s Government has formed and maintained the most intimate connexions, and to whose Governments Great Britain has paid for the right of active intervention in order to its complete extirpation."[53] So zealous was Stevenson, our minister to England, in denying the Right of Search, that he boldly informed Palmerston, in 1841, “that there is no shadow of pretence for excusing, much less justifying, the exercise of any such right.  That it is wholly immaterial, whether the vessels be equipped for, or actually engaged in slave traffic or not, and consequently the right to search or detain even slave vessels, must be confined to the ships or vessels of those nations with whom it may have treaties on the subject."[54] Palmerston courteously replied that he could not think that the United States seriously intended to make its flag a refuge for slave-traders;[55] and Aberdeen pertinently declared:  “Now, it can scarcely be maintained by Mr. Stevenson that Great Britain should be bound to permit her own subjects, with British vessels and British capital, to carry on, before the eyes of British officers, this detestable traffic in human beings, which the law has declared to be piracy, merely because they had the audacity to commit an additional offence by fraudulently usurping the American flag."[56] Thus the dispute, even after the advent of Webster, went on for a time, involving itself in metaphysical subtleties, and apparently leading no nearer to an understanding.[57]

In 1838 a fourth conference of the powers for the consideration of the slave-trade took place at London.  It was attended by representatives of England, France, Russia, Prussia, and Austria.  England laid the projet of a treaty before them, to which all but France assented.  This so-called Quintuple Treaty, signed December 20, 1841, denounced the slave-trade as piracy, and declared that “the High Contracting Parties agree by common consent, that those of their ships of war which shall be provided with special warrants and orders ... may search every merchant-vessel belonging to any one of the High Contracting Parties which shall, on reasonable grounds, be suspected of being engaged in the traffic in slaves.”  All captured slavers were to be sent to their own countries for trial.[58]