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.

  • I think that people would answer this question differently according to whether they consider abortion to be inherently wrong. Commented Jun 3, 2019 at 23:56
  • @Nate I know that. What I'm interested in is whether this has been analyzed from a purely legal perspective (not a religious one or one based on personal moral sentiments), or whether a court has ruled on it. Commented Jun 4, 2019 at 0:01
  • Many of the places you have used "f" in your quotation should be "ſ". If you find the long-s difficult to enter, the correct replacement is 's', not 'f' which is a completely different letter. Commented Dec 2, 2019 at 8:45
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    @martin actually, I recognized that, but the source I found this at had already substituted the "f", so that's what I got. Commented Dec 2, 2019 at 12:01

5 Answers 5


While they didn't explicitly consider the malum distinction you ask about, the US Supreme Court in Roe vs Wade looked at the historical background to abortion law. The relevant part is section VI, which begins:

It perhaps is not generally appreciated that the restrictive criminal abortion laws in effect in a majority of States today are of relatively recent vintage. Those laws, generally proscribing abortion or its attempt at any time during pregnancy except when necessary to preserve the pregnant woman's life, are not of ancient or even of common law origin. Instead, they derive from statutory changes effected, for the most part, in the latter half of the 19th century.

The rest of the section analyses a bunch of historical legal sources in support of this statement.

Based on the references they cite it would seem that abortion before quickening is (or was) considered Malum Prohibitum while after quickening it was Malum in Se.

  • What is meant by before "quickening"? Commented Apr 5, 2023 at 22:07
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    @Seekinganswers It's when the mother first feels the fetus moving. Commented Apr 6, 2023 at 8:53

This distinction was once important in English law, and other common-law systems derived from it, because common-law courts felt free to punish a Malum in Se even when there was no relevant statute, while a Malum Prohibitum would be punished only if it violated a specific statute.

But today in the US, and to a large degree in the UK and other common-law countries, nearly all law has a statutory basis (although subject to interpretation by courts). Thus the distinction between Malum in Se and Malum Prohibitum no longer makes a significant difference, and is pretty much purely academic, except in a historical context.

  • Common law offenses do still exist to some extent in the US. Michigan, for example, sets out statutory penalties for murder, but offers no statutory definition of the word "murder" (it does give a definition, but it is defining "murder in the first degree" in terms of "murder" - it never explicitly says something like "murder is the unlawful killing of a human being with malice aforethought").
    – Kevin
    Commented Nov 11, 2022 at 4:22

Legally, its largely irrelevant

It is worth noting that the case Wikipedia cites for the definition is 114 years old - hardly a current precedent.

Historically, the distinction, which was first stated in 1496 had to do with what crimes the Crown could authorize in advance (Malum Prohibitum) and those it couldn't (Malum in Se). Of course it could (and can) pardon offences after they are committed. It also allowed the courts to - generate shall we say - common law crimes if they fell into Malum in Se category i.e. a crime that didn't exist in the law until the particular facts of a case required it.

Throughout the 20th century, most common law jurisdictions have to a large extent (and in some cases totally) replaced common-law crimes with statutory crimes. That is the Malum in Se category has been abolished and the Malum Prohibitum case has totally supplanted it. In jurisdictions where this change is not yet total, sufficient precedent exists in criminal matters so that the chance a judge needs to create a crime from first principles are infinitesimally small - even unique facts can be shoehorned into existing legal principles.

As to the particular question on abortion - try posting it on philosophy as its not a legal question.


English Law Answer:

"Anglo-American Common Law generally divides criminal offenses into two categories...Mallum se and mallum prohibitum"

If you include english law within the scope of Anglo-American Common Law, then I must disagree with the above statement. English law does not distinguish crimes based on whether they exist in as a 'natural moral wrong' or whether they are prohibited by virtue of statute. Perhaps this is a categorisation present in American law it is not something we are taught or practice in the courts of England and Wales.

That said, to remain faithful to the spirit of the question, a more suitable distinction in English law would be common law crimes as opposed to statutory crimes.

A common law crime is one that exists because of decisions of courts. For example, murder Is a common law crime. There is no statute in english law that defines murder. There is no statute that says murder is illegal. Interestingly the Homicide Act 1957 establishes some legal defences to murder, but does not define murder itself, nor establish it as a crime.

A crime under statute would be what the question describes a mallus prohibitum, something forbidden by word of law.

Anyway, regarding the question of whether abortion is an innately immoral act. Firstly, english law doesnt make all immoral acts illegal, therefore even if one were to assume abortion as an immoral act, it does not logically follow that it would be illegal. Secondly, the abortion act 1967 explicitly states that abortion is legal (under the circumstances listed out in section 1). As parliament is sovereign, this act supercedes any common law ban on abortion (if any).

The wording of the act does raise the question, if an abortion is performed and does not constitute a legal abortion under the reauirements of the act, has a crime been committed, and if so, what crime? Some may argue murder. Though i cannot say for sure if that would be the case.

  • Have you read Blackstone's Commentaries? He makes a big deal of the difference between a "natural moral wrong" and something prohibited because Parliament passed a law against it. Commented Jun 4, 2019 at 1:54
  • I do have a copy of blackstones criminal practice on me, though you are probably referring to blackstones commentaries on the laws of england. I highly doubt the author of the text 'makes a big deal of the difference between a natural moral wrong and something prohibited because parliament passed a law against it". Id be glad to read and discuss any commentary to that effect if you can find me the appropriate reference Commented Jun 4, 2019 at 2:01
  • Alternatively, if you refer to any other blackstones text please provide me a source. If such commentary exists i would very much like to read it, as it may prove interesting (though not useful due to the age of blackstones commentaries) in a judicial review context. If you mean the commentaries on the laws of england then you really will have to provide a reference as the text is simply huge Commented Jun 4, 2019 at 2:04
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    I updated my question with a quotation from Blackstone expressing the difference. Commented Jun 4, 2019 at 2:14

Malum in se is defined as: “A wrong in itself; an act or case involving illegality from the very nature of the transaction, upon principles of nature, moral, and public law. . . . Such are most or all of the offenses cognizable at common law (without the denouncement of statute).” Black’s Law Dictionary 865 (5th ed. 1979).

In Commonwealth v. Parker, 50 Mass. 263, 265-66, (1845), it was held: “The use of violence upon a woman, with an intent to procure her miscarriage, without her consent, is an assault highly aggravated by such wicked purpose, and would be indictable at common law. So where, upon a similar attempt by drugs or instruments, the death of the mother ensues, the party making such an attempt, with or without the consent of the mother, is guilty of the murder of the mother, on the ground that it is an act done without lawful purpose, dangerous to life, and that the consent of the woman cannot take away the imputation of malice, any more than in case of duel, where, in like manner, there is consent of the parties.”

Even Cyril C. Means, Jr., legal counsel for the National Association for the Reform of Abortion (NARAL). had to admit that for both a quickened and unquickened fetus, “If she died in consequence of the procedure, he [the abortionist] was guilty of murder.” Means, The Law of New York Concerning Abortion and the Status of the Foetus, 1664-1968: A Case of Cessation of Constitutionality, 14 N.Y.L.F. 411, 501 (1968). So, in all cases, whether there was evidence the child in the womb was alive, “quickened,” or not, abortion was always malum in se. The question in criminal law cases, was whether there was sufficient evidence of the malum in se crime to indict.

In Peoples v. Commonwealth, 87 Ky. 487, 490, 493, 9 S.W. 509, 510, [1888] it was decided unnecessary to allege that the mother was quick with child. The court said: “The act was not only immoral, violative of the law of nature, and deliberate in character, but reckless of life, and wrongful per se…" In considering a charge of soliciting and inciting a pregnant woman to take certain drugs to cause an abortion, it was said, in Lamb v. State, 67 Md. 524, 533, 10 Atl. 208 [a case cited by Blackmun, 410 U.S. 136 n. 28], that by the ancient common law it was not regarded as a criminal offense to commit an abortion in the early stages of pregnancy, but, "A considerable change in the law has taken place in many jurisdictions by the silent and steady progress of judicial opinion; and it has been frequently held by Courts of high character that abortion is a crime at common law without regard to the stage of gestation."

As for the common law, Justice Blackmun had made the incredulous assertion that “[I]t now appear[s] doubtful that abortion was ever firmly established as a common-law crime even with respect to the destruction of a quick fetus.” 410 U.S. 113, 136. To the contrary, abortion was in practice a common law crime in America at the time Roe v. Wade was being decided per State v. Barquet, 262 So.2d 431, 437 (Fla. 1972), a case which Justice Blackmun had cited in Roe. 410 U.S. 113, 155. In Barquet, the Florida Supreme Court struck down for vagueness state statutes which outlawed abortion except when “necessary to preserve the life of such mother,” under both the federal Fourteenth Amendment and the Florida Constitution’s due process clause. 262 So.2d at 433, 438. But, by having struck down the statutory law that had replaced the common law crime of abortion, the common law crime of abortion was now again applicable. Fla. Stat., tit. 46, § 775.01. Consequently, the Florida Supreme Court went on ultimately to hold (262 So.2d at 437): Our conclusion creates a tremendous problem in that the common law is now brought into play. It was a crime at common law to operate upon a pregnant woman for the purpose of procuring an abortion if she were actually quick with child. 1 F.L.P., Abortion, § 2, citing Eggart v. State, 40 Fla. 527, 25 So. 144 (1898); 1 Am.Jur.2d, Abortion, § 1. “Quick” means “living; alive.” Black’s Law Dictionary, [1415] (4th Ed. 1957). From the filing of this opinion until a statute is enacted by the Legislature, a person may be charged with the common law offense of abortion.

Significantly, the Florida Legislative Council adopted “the ‘Common Law’ as it existed in England on July 4, 1776.

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