The "justifiable homicide" defense was attempted by the murderer of Dr. Tiller in Kansas quite recently, and failed (according to the analysts) primarily because of the lack of definition of "a fetus as a person" during the period in which abortions are legal, or a sufficiently specific definition of the killing of a fetus as the killing of a person.

The SD bill is an apparent attempt to establish contrary precedent.

"if there is reasonable ground to apprehend a design to commit a felony" quite clearly is an attempt to subvert the other definitions - including the fetal homicide one.

In most states, there are quite specific rules on the validation of a need for an abortion, and consent for one to be performed. The failure to do all the specifically enumerated requirements prior to performing any abortion is frequently a felony.

The former Attorney General principally responsible for extreme harassment of Dr Tiller over a period of several years is currently under indictment for illegal and unethical conduct in office for a number of his actions in the matter. That AG filed multiple charges of "felonies in the performing of abortions" against Tiller (all of which failed).

From the Mother Jones link:

The bill in South Dakota is an invitation to murder abortion providers," says Vicki Saporta, the president of the National Abortion Federation, the professional association of abortion providers. Since 1993, eight doctors have been assassinated at the hands of anti-abortion extremists, and another 17 have been the victims of murder attempts. Some of the perpetrators of those crimes have tried to use the justifiable homicide defense at their trials.

It is not necessary actually to legalize murder, if one can give the illusion of a viable defense to a few nut-cases. The SD bill seems (to many people) clearly intended to incite actions that it can't, for now, specifically legalize.

John