The state offering to kill people whose ability to give consent is compromised by their mental instability is certainly comparable, as is the state-funded termination of pregnancies where the baby is believed to have Down Syndrome or prenatal anomalies. The slippery-slope argument, which was ridiculed re: legalization of gay marriage and has been proven conservative in terms of impact, certainly applies here.

As for the comparative: "October 1939 Hitler authorizes killing of the impaired Adolf Hitler authorizes the beginning of the Euthanasia Program—the systematic killing of those Germans whom the Nazis deem "unworthy of life." The order is backdated to the beginning of the war (September 1, 1939). At first, doctors and staff in hospitals are encouraged to neglect patients. Thus, patients die of starvation and diseases. Later, groups of "consultants" visit hospitals and decide who will die. Those patients are sent to various "euthanasia" killing centers in Greater Germany and killed by lethal injection or in gas chambers."