Garnet was a member of the militant school of abolitionism, which included David Walker, John Brown, and Harriet Tubman, among others. He felt the moderate Garrisonians, led by William Lloyd Garrison, were too paternalistic, and that their position that slavery would end through moral suasion was a domed policy. He advocated the use of slave rebellions, led by the enslaved, and assisted by free Afrikan Americans as the most realistic solution. Garnet made this argument in his famous speeches, "Call to Rebellion," when he delivered it in August 1843, at the National Negro Convention in Buffalo, New York. This speech is considered the most powerful speech delivered by an Afrikan American until King made his “I Have a Dream” speech more than a century later. Garnet argued armed rebellion was the most effective way to end slavery. The Convention voted to adopt the the speech. In addition to the speech there were several resolution that would have also aligned the convention with the platform of the newly formed Liberty Party. These resolutions were opposed by the Garrisonians, particularly Frederick Douglass and Charles Lenox, who were both paid lecturers by Garrison's network of organizations. Though the resolutions were eventually adopted, the speech was narrowly defeated by the influence of the same Garrisonians, who thought Garnet's ideas were too radical and could damage the cause by arousing too much fear and resistance among whites. The Garrisons preached nonviolence arguing moral suasion alone would end slavery. Douglass commenting on the speech said it contained “too much physical force in both the address and speaker.” But on the eve of the Civil War, Douglass had changed his position, and he even met with Lincoln to convince him to let Afrikan Americans fight in the Civil War. Douglass although a leader in the abolitionist movement, he was more accurately the leading Garrisonian abolitionist, which was a particular school of abolitionists.
Garnet continued to argue for more direct action, and he later with financial assistance from John Brown, reprinted militant abolitionist David Walker's Appeal, along with his speech, “Call to Rebellion” circulating it in the black communities. Douglass was also acquainted with the militant abolitionist John Brown and had visited his home two month before Harper's Ferry. Though he disapproved of Brown's plan, after the raid fearing guilt by association and arrest as a co-conspirator, Douglass fled to Canada.
Garnet felt the Constitution was a document that could be used in the fight against slavery, thus he was an early member and organizer for the Liberty Party. The Party was an early advocate of the abolitionism. The party included abolitionists, many black abolitionists, who were willing to work within electoral politics to try to influence people to support their goals. In contrast, the Garrisonians argued the the Constitution was a proslavery document and should be condemned. The Garrisonians, Douglass included opposed voting and working within the system. By 1860, however, Douglass came to agree with Garnet and others that the Constitution was an anti-slavery document. Douglass, eventually would split with the Garrisonians, as the militant abolitionists had earlier. If the Constitution had not been viewed as such or at least neutral then the fight for Afrikan American freedom on legal grounds would have been impossible. The NAACP's legal attack on Jim Crow, using the Constitution as its basis, would not have evolved as a stratagem to fight discrimination.
Garnet was appointed a U.S. Minister to Liberia, where he died in 1882. For many years, Douglass did not speak to Garnet, however, Douglass known for his ability to forgive mourned Garnet's passing and noted his achievements. Five years earlier, Douglass had visited Thomas Auld, his former master who was by then on his deathbed, and the two men reconciled. Douglass and Garnet though rivals while living, history has forgotten one of them. The reason why is obvious. Garnet was the more radical of the two, treading a path the few follow. Douglass' stances were usually more accommodating. On this birthday of Frederick Douglass let us remember his nemesis, the Reverend Henry Highland Garnet too.