Where the actual parallel exists is the JUSTIFICATION of slavery, the Holocaust, and abortion uses the same process: the dehumanization of the target group. We justified slavery because slaves were not "human enough" to be allowed human rights. Hitler justified the holocaust, his followers supported his conclusions, and much of the public had little to no objection because the Jews were deamed to not be "human enough" to warrant respect and equality. Native Americans were killed, and a determined program of genocide waged against us because we were not "human enough" to be called "persons" under the law. Each and every time through history, people have justified calling a selected group or class of humans as being "not human enough" based on some observed differences (or in some cases, perceived) between the targeted group, and the rest of "real" humans.