 In 1840, however, when the society began to advocate measures which he deemed too radical, he withdrew his membership, but with his pen he continued his labor on behalf of the slave, urging emancipation in the District of Columbia and the exclusion of slavery from the territories, though deprecating any attempt to interfere with slavery in the states.He was also a proponent of antiwar theories and was for many years president of the Peace Society.His pamphlet "War and Peace