Garrison promptly threw down his challenge to Elliott Cresson, offering to prove him an impostor and the Colonization Society “corrupt in its principles, proscriptive in its measures, and the worst enemy of the free colored and slave population of the United States.”  From the first it was apparent that Cresson did not mean to encounter the author of the “Thoughts” in public debate.  Even a mouse when cornered will show fight, but there was no manly fight in Cresson.  Garrison sent him a letter containing seven grave charges against his society, and dared him to a refutation of them in a joint discussion.  This challenge was presented four times before the agent of colonization could be persuaded to accept it.  Garrison was bent on a joint public discussion between himself and Mr. Cresson.  But Mr. Cresson was bent on avoiding his opponent.  He skulked under one pretext or another from vindicating the colonization scheme from the seven-headed indictment preferred against it by the agent of the New England Anti-Slavery Society.  As Cresson could not be driven into a joint discussion with him there was nothing left to Garrison but to go on without him.  His arraignment and exposure of the society in public and private was thorough and overwhelming.  He was indefatigable in the prosecution of this part of his mission.  And his labor was not in vain.  For in less than three months after his reaching England he had rendered the Colonization Society as odious there as his “Thoughts” had made it in America.  The great body of the anti-slavery sentiment in Great Britain promptly condemned the spirit and object of the American Colonization Society.  Such leaders as Buxton and Cropper “termed its objects diabolical;” while Zachary Macaulay, father of the historian, did not doubt that “the unchristian prejudice of color (which alone has given birth to the Colonization Society, though varnished over with other more plausible pretences, and veiled under a profession of a Christian regard for the temporal and spiritual interests of the negro which is belied by the whole course of its reasonings and the spirit of its measures) is so detestable in itself that I think it ought not to be tolerated, but, on the contrary, ought to be denounced and opposed by all humane, and especially by all pious persons in this country.”

The protest against the Colonization Society “signed by Wilberforce and eleven of the most distinguished Abolitionists in Great Britain,” including Buxton, Macaulay, Cropper, and Daniel O’Connell, showed how thoroughly Garrison had accomplished his mission.  The protest declares, thanks to the teachings of the agent of the New England Anti-Slavery Society, that the colonization scheme “takes its roots from a cruel prejudice and alienation in the whites of America against the colored people, slave or free.  This being its source the effects are what might be expected; that it fosters and increases the spirit of caste, already so unhappily predominant; that it