States could never suppress or even limit the
trade without systematic co-operation. In 1817 a committee of the House
had urged the opening of negotiations looking toward such international
co-operation,[29] and a Senate motion to the same effect had caused long
debate.[30] In 1820 and 1821 two House committee reports, one of which
recommended the granting of a Right of Search, were adopted by the
House, but failed in the Senate.[31] Adams, notwithstanding this, saw
constitutional objections to the plan proposed by Canning, and wrote to
him, December 30: "A Compact, giving the power to the Naval Officers of
one Nation to search the Merchant Vessels of another for Offenders and
offences against the Laws of the latter, backed by a further power to
seize and carry into a Foreign Port, and there subject to the decision
of a Tribunal composed of at least one half Foreigners, irresponsible to
the Supreme Corrective tribunal of this Union, and not amendable to the
controul of impeachment for official misdemeanors, was an investment of
power, over the persons, property and reputation of the Citizens of this
Country, not only unwarranted by any delegation of Sovereign Power to
the National Government, but so adverse to the elementary principles and
indispensable securities of individual rights, ... that not even the
most unqualified approbation of the ends ... could justify the
transgression." He then suggested co-operation of the fleets on the
coast of Africa, a proposal which was promptly accepted.[32]

The slave-trade was again a subject of international consideration at
the Congress of Verona in 1822. Austria, France, Great Britain, Russia,
and Prussia were represented. The English delegates declared that,
although only Portugal and Brazil allowed the trade, yet the traffic was
at that moment carried on to a greater extent than ever before. They
said that in seven months of the year 1821 no less than 21,000 slaves
were abducted, and three hundred and fifty-two vessels entered African
ports north of the equator. "It is obvious," said they, "that this crime
is committed in contravention of the Laws of every Country of Europe,
and of America, excepting only of one, and that it requires something
more than the ordinary operation of Law to prevent it." England
therefore recommended:--

1. That each country denounce the trade as piracy, with a view of
founding upon the aggregate of such separate declarations a general law
to be i