Garrison’s assertion that “the overthrow of the Colonization Society was the overthrow of slavery itself,” was, from the standpoint of a student of history, an exaggerated one.  We know now that the claim was not founded on fact, that while they did stand together they did not fall together.  But the position was, nevertheless, the strongest possible one for the anti-slavery movement to occupy at the time.  In the disposition of the pro-slavery forces on the field of the opening conflict in 1832, the colonization scheme commanded the important approaches to the citadel of the peculiar institution.  It cut off the passes to public opinion, and to the religious and benevolent influences of the land.  To reach these it was necessary in the first place to dislodge the society from its coign of vantage, its strategical point in the agitation.  And this is precisely what “The Thoughts on African Colonization” did.  It dislodged the society from its powerful place in the moral sentiment of the North.  The capture of this position was like the capture of a drawbridge, and the precipitation of the assaulting column directly upon the walls of a besieged castle.  Within the pamphlet was contained the whole tremendous enginery of demolition.  The anti-slavery agent and lecturer thenceforth set it up wherever he spoke.

To him it was not only the catapult; it furnished the missile-like facts and arguments for breaching the walls of this pro-slavery stronghold as well.

The effect of the publication of “The Thoughts” in this country was extraordinary, but the result of their circulation in England was hardly less so.  It produced there as here a revolution in public sentiment upon the subject.  The philanthropy and piety of Great Britain had generally prior to the unmasking of the society, looked upon it as an instrument of Emancipation, and had accordingly given it their powerful countenance, and not a little material support.  But from the moment that the pamphlet reached England a decided change in this regard became manifest.  The society made fruitless attempts to break the force of the blow dealt it by Garrison in the United States.  But wherever its emissaries traveled “The Thoughts” confronted and confounded them.  So that Mr. Garrison was warranted in saying that “all that sophistry or misrepresentation could effect to overthrow its integrity has been attempted in vain.  The work, as a whole, stands irrefutable.”  The attempts made to maintain its hold upon the British public were characterized by duplicity and misrepresentation beyond anything practiced in America.  The work of deceiving the philanthropy of Great Britain was conducted by the emissary of the society, Elliott Cresson, a man perfectly fitted to perform his part with remarkable thoroughness and industry.  Three thousand miles away from America, and practically secure from contradiction, he went about making outrageous statements as to the anti-slavery character and purpose of the colonization enterprise.  As there was no one in England sufficiently acquainted with the operations and designs of the society, he was enabled to falsify facts, to conceal the real principles of the scheme with astonishing audacity and activity.  He approached Wilberforce, and duped Clarkson into a belief in the anti-slavery aim of the society.