Anglo-American Common Law generally divides criminal offenses into two categories. Malum in Se offenses are inherently wrong. This includes traditional offenses such as Murder, Robbery, and Assault. Some sources define the concept as encompassing acts that would be wrong even if there was no specific law against it. Malum Prohibitum offenses, on the other hand, are not inherently wicked acts - they are just against the law for whatever reason (often public order, safety, or health). Common examples of such offenses are DUI, carrying a concealed firearm without a permit, evading an immigration checkpoint, and possessing a controlled substance.
Wikipedia cites:
Criminal offenses can be broken down into two general categories malum in se and malum prohibitum. The distinction between malum in se and malum prohibitum offenses is best characterized as follows: a malum in se offense is "naturally evil as adjudged by the sense of a civilized community," whereas a malum prohibitum offense is wrong only because a statute makes it so. State v. Horton, 139 N.C. 588, 51 S.E. 945, 946 (1905).
Also see Book 4, Chapter 1 of Blackstone's Commentaries on the Laws of England, in which he states (my emphasis)
AS to the power of human punifhment, or the right of the temporal legiflator to inflict difcretionary penalties for crimes and mifdemefnors. It is clear, that the right of punifhing crimes agianft the law of nature, as murder and the like, is in a ftate of mere nature vefted in every individual. For it muft be vefted in fomebody ; otherwife the laws of nature would be vain and fruitlefs, if none were empowered to put them in execution : and if that power is vefted in any one, it muft alfo be vefted in all mankind ; fince all are by nature equal. Whereof the firft murderer Cain was fo fenfible, that we find him expreffing his apprehenfions, that whoever fhould find him would flay him. In a ftate of fociety this right is transferred from individuals to the fovereign power ; whereby men are prevented from being judges in their own caufes, which is one of the evils that civil government was intended to remedy. Whatever power therefore individuals had of punifhing offences aginft the law of nature, that is now vefted in the magiftrate alone ; who bears the fword of juftice by the confent of the whole community. And to this precedent natural power of individuals muft be referred that right, which fome have argued to belong to every ftate, (though, in fact, never exercifed by any) of punifhing not only their own fubjects, but alfo foreign embaffadors, even with death itfelf ; in cafe they have offended, not indeed againft the municipal laws of the country, but againft the divine laws of nature, and become liable thereby to forfeit their lives for their guilt.
AS to offences merely againft the laws of fociety, which are only mala prohibita, and not mala in fe ; the temporal magiftrate is alfo empowered to infict coercive penalties for fuch tranfgreffions : and this by the confent of individuals ; who, in forming focieties, did either tacitly or expreffly inveft the fovereign power with a right making laws, and of enforcing obedience to them when made, by exercifing, upon their nonobfervance, feverities adequate to the evil. The lawfulnefs therefore of punifhing fuch criminals is founded upon this principle, that the law by which they fuffer was by their own confent ; it is part to the original contract into which they entered, when firft they engaged in fociety ; it was calculated for, and has long contributed to. their own fecurtiy.
Is obtaining an abortion contrary to local law a malum in se or a malum prohibitum offense? I can think of arguments in favor of either:
Illegal abortions are Malum In Se
- Abortion is often considered by opponents as a form of Murder, which is a traditional malum in se offense.
- Arguments against abortion are often couched in moralistic terms, rather than arguments based on public good. That is, activists typically claim that banning abortion is a moral or religious duty rather than claiming that banning it would improve people's health, build the economy, reduce pollution, or make elections fairer for minority candidates.
Illegal abortions are Malum Prohibitum
- Laws on when, if, and how an abortion may be lawfully performed vary significantly from jurisdiction to jurisdiction. A law based on a timeless moral "truth" would be expected to be harmonious nearly everywhere.
Restated, is Abortion inherently a Malum in Se act, with statutes in various places changing the rule to allow it in certain scenarios, or is abortion inherently permitted according to the Common Law view of morality, with modern anti-abortion laws being strictly statutory in nature?
As Nate Eldredge mentioned, I am aware that some people may approach this from the perspective of their own religious or moral views. What I'm interested in is whether this has been analyzed from a purely legal perspective or whether a court has ruled on it.