tive abolition of a Commerce so
odious, and so strongly condemned by the laws of religion and of
nature."[21]

Treaties further restricting the trade continued to be made by Great
Britain: Spain abolished the trade north of the equator in 1817,[22] and
promised entire abolition in 1820; Spain, Portugal, and Holland also
granted a mutual limited Right of Search to England, and joined in
establishing mixed courts.[23] The effort, however, to secure a general
declaration of the powers urging, if not compelling, the abolition of
the trade in 1820, as well as the attempt to secure a qualified
international Right of Visit, failed, although both propositions were
strongly urged by England at the Conference of 1818.[24]

69. ~The Struggle for an International Right of Search, 1820-1840.~
Whatever England's motives were, it is certain that only a limited
international Right of Visit on the high seas could suppress or greatly
limit the slave-trade. Her diplomacy was therefore henceforth directed
to this end. On the other hand, the maritime supremacy of England, so
successfully asserted during the Napoleonic wars, would, in case a Right
of Search were granted, virtually make England the policeman of the
seas; and if nations like the United States had already, under present
conditions, had just cause to complain of violations by England of their
rights on the seas, might not any extension of rights by international
agreement be dangerous? It was such considerations that for many years
brought the powers to a dead-lock in their efforts to suppress the
slave-trade.

At first it looked as if England might attempt, by judicial decisions in
her own courts, to seize even foreign slavers.[25] After the war,
however, her courts disavowed such action,[26] and the right was sought
for by treaty stipulation. Castlereagh took early opportunity to
approach the United States on the matter, suggesting to Minister Rush,
June 20, 1818, a mutual but strictly limited Right of Search.[27] Rush
was ordered to give him assurances of the solicitude of the United
States to suppress the traffic, but to state that the concessions asked
for appeared of a character not adaptable to our institutions.
Negotiations were then transferred to Washington; and the new British
minister, Mr. Stratford Canning, approached Adams with full instructions
in December, 1820.[28]

Meantime, it had become clear to many in the United States that the
individual efforts of