"This simply is to bring consistency to South Dakota statute as it relates to justifiable homicide," said Jensen in an interview, repeating an argument he made in the committee hearing on the bill last week. "If you look at the code, these codes are dealing with illegal acts. Now, abortion is a legal act. So this has got nothing to do with abortion."
It means it would be possible to use a defence of justified homicide if you used force to protect an unborn child from an illegal assault.
UK murder laws are completely different, but it is worth noting that there is an offence of child destruction - so illegal harm to the unborn also falls within the criminal justice system here.