 He was an activist involved in the abolitionist movement on many fronts: he participated in the Underground Railroad, protested against the Fugitive Slave Law, and gave support to John Brown and his party. Most importantly perhaps, he provides a justification for principled revolt and a method of nonviolent resistance, both of which would have a considerable influence on revolutionary movements in the twentieth century. In his essay on “Civil Disobedience,” originally published as “Resistance to Civil Government,” Thoreau defends the validity of conscientious objection to unjust laws, which he claims ought to be transgressed at once. Political institutions as such are regarded by him with distrust, and although he arguably overestimates the extent to which it is possible to disassociate oneself from them, he convincingly insists that social consensus is not a guarantee of rectitude or truth. One of the most valuable points he makes against the critics of John Brown is that a person should not be dismissed as “insane” by virtue of dissenting from the majority: Brown’s anger is grounded upon an awareness of the fact that slavery is a violation of human rights, and Thoreau berates the law-abiding citizens of Massachusetts for looking the other way (“A Plea for Captain John Brown”). Passively and quietly allowing an unjust practice to continue is tantamount to collaborating with evil, he claims, articulating a principle of noncompliance that would inspire the philosophically informed nonviolent resistance of Gandhi and Martin Luther King, among others.