The influential leader who advocated for civil disobedience in the United States was Henry David Thoreau. In his essay "Civil Disobedience," written in 1849, Thoreau articulated the idea that individuals should not allow governments to overrule their consciences and that it is right to resist unjust laws. This philosophy deeply influenced future civil rights leaders, most notably Martin Luther King Jr., who adopted Thoreau's principles in his nonviolent resistance against racial discrimination. Thoreau's emphasis on individual moral judgment and passive resistance against unjust governance continues to resonate within movements advocating social change and justice.