Pressure to abolish slavery within the British Empire was already mounting in Britain in the mid-1820s. This effort would achieve success in 1833, when Britain emancipated 780,000 slaves, paying 20 million pounds sterling compensation to their owners and requiring the former slaves to work for a term as "apprentices."
In an effort to assist opponents of the African slave trade, the United States came close to agreeing in 1824 to allow Britain to search the ships of American slave traders. In this letter, President Monroe explains the agreement. By defining the slave trade as piracy, British ships would be allowed to stop and board American slave trading vessels, without arguments over sovereignty or affronts to American shipping. The measure was defeated, however, in the Senate.
Monroe was a sincere enemy of the African slave trade and was more liberal on the slavery issue than many historians have thought. Yet in this letter he exresses the clear view that emancipation in the British colonies would provide a dangerous precedent for the future. This document is valuable for suggesting that slavery was the supreme political issue in the United States, even if discussion was largely suppressed. The United States failed to attend a hemispheric conference on slavery and other matters in Panama in 1824, the year this letter was written.
I hear that the convention lately concluded with G[reat]. B[ritain]., whereby the crime of piracy, is attached to the slave trade, is in danger of being rejected, as Congress made that trade, piratical, by law, and the H[ouse] of R[representatives] recommended it, by a resolution, which passed almost unanimously, to the Executive, to endeavour, by negotiation & treaty, with other powers, to make the trade piracy by the law of nations, the rejection of this convention, would in my opinion, produce very serious mischief. I hear with deep concern, that some of our estimable friends, to the South, are opposed to it, but on what grounds I know not. The British government wished, to adopt, & make general, a different plan, that is, to extend the right of search, which is a belligerent right, to a time of peace, & to board vessels on that principle. We feared that this right thus sanctioned, would be subject to abuse, in the hands of the superior naval power, and therefore declined it. Under the authority of Congress, we went further; the trade was made piratical, and the right of entry would rest on the crime, which it became the law of nations would be common to all....
As to the motives imputed to Mr. Canning [the British Prime Minister], of acceding to our project, to sustain himself in England, admit the fact, & what the consequences? The Wilberforce party [the British abolitionists] are pushing the policy of liberating the slaves in the W. Indies, to which Mr. Canning [the Prime Minister] is opposed. By adopting our treaty, and making the trade piratical, he showed to that party, that he was as averse to the trade as they were, altho' he was not willing to disturb the existing state in the Colonies, & ruin the people there. Which of the parties, the Wilberforce or ministerial, ought we to strengthen, or in other words, ought we to promote the emancipation of slaves in the W. Indies, or the retaining things in their present state there? In every light that I can view the subject, I should consider the rejection of this treaty as the most dangerous measure.