My post about the possible unconstitutionality of strict liability gun control laws — i.e., of laws that hold someone criminally liable even if he's made an honest mistake (or perhaps even a reasonable mistake) about some fact, such as whether he's a felon, whether the gun is fully automatic, and the like — reminds me of the broader question of strict liability and constitutional rights. And this question most clearly arises as to strict liability for sex with people who are underage.
The Court has repeatedly held that strict criminal liability for speech — even constitutionally unprotected speech — is impermissible, and strict civil liability in such cases often is, too. The rationale is that strict liability for conduct tends to deter not just the punished conduct (which by hypothesis should be deterred), but also other conduct as to which the actor harbors some fear that it might be punishable. Sometimes, that overdeterrence is fine. But when the deterred other conduct is itself constitutionally protected, such overdeterrence excessively burdens the constitutional right.
Thus, strict liability for child pornography (imposed even if a distributor or possessor doesn't know, and has no reason to know, that the actor in a pornographic movie is under 18) would deter not only distribution and possession of constitutionally unprotected child pornography but even of constitutionally protected sexually themed material that doesn't involve under-18-year-olds (since some people would be afraid that they'd go to prison for years because an actor who looks adult was actually underage). Likewise, strict liability for possession of fully automatic guns (cf. the Washington case, mentioned here) would deter not only constitutionally unprotected possession of full automatics, but also constitutionally protected possession of semiautomatics, if someone fears that the semiautomatic might have been modified to function as a full automatic (or might function that way because of some defect). And strict liability for abortions performed on minors without the parent's permission (even when the minor shows a forged parental consent form, or brings along someone whom she falsely describes as her parent) would unacceptably deter not only constitutionally unprotected abortions without parental consent, but also constitutionally protected abortions with parental consent, if the doctor fears that any abortion on a minor will possibly expose him to liability.
What then about strict liability for sex with people under age 18, which some states still maintain? Consider this comparison chart:
|Constitutionally unprotected conduct||Constitutionally protected conduct||Result|
|Child pornography constitutionally unprotected: People who make, distribute, and possess movies that contain minors in sexual situations may be punished. New York v. Ferber.||Other speech constitutionally protected: If the actors and actresses are 18 or older, the movie is protected (unless it fits within the obscenity exception).||It's unconstitutional to hold people strictly liable for reasonable mistakes of fact about the actors' or actresses' ages — "I reasonably thought she was 18" is a good defense [UPDATE: at least as to distribution or possession, the issues discussed in Ferber and later cases]. Ferber.|
|Machinegun possession constitutionally unprotected. D.C. v. Heller||Non-machinegun possession constitutionally protected.||It may well be unconstitutional to hold people strictly liable for machinegun possession, even when they've made a mistake (or perhaps just when they've made a reasonable mistake) as to whether the gun is a machinegun.|
|Abortions performed without parental consent (or judicial bypass) on minors constitutionally unprotected.||Abortions performed with parental consent on minors constitutionally protected.||It's unconstitutional (according to a state court of appeals decision) to hold people strictly liable for performing an abortion on a minor without the parent's consent, even when they've made a mistake (or perhaps just when they've made a reasonable mistake) as to whether the consent was given, or whether the person was a minor.|
|Sex with minors constitutionally unprotected.||Sex with consenting adults protected. Lawrence v. Texas.||Shouldn't it be unconstitutional to hold people strictly liable for reasonable mistakes of fact about their partners' ages? Shouldn't "I reasonably thought she was 18" must be a good defense, as it is when one is tried for distributing or possessing child pornography, or as it is when one is tried for performing an illegal abortion, or as it likely would be (changing the facts appropriately) when one is tried for illegally possessing a weapon.|
What are the possible distinctions here? One is that there's no right, under Lawrence, to have sex with minors — but for reasons I mention, that doesn't distinguish the free speech cases, which likewise bar strict liability even for constitutionally unprotected behavior, because such liability may deter protected behavior.
A second distinction — that preventing statutory rape is just very important — also fails. Preventing child pornography involving minors is also very important, but the Court has held that the government must fight that by punishing knowing, reckless, or possibly negligent use of minors; the government may not serve even this very important interest by punishing people who reasonably believed that the person was 18.
Another is a factual distinction: In practice, one might say, very few people will be deterred from having sex with 18-year-old girls because they fear that she might be 17. But why? One might argue that it's because sex is such a powerful force; but so is the desire to make money from selling obscenity or child pornography, for those who are in that business. One might also point out that because statutory rape laws are notoriously underenforced, few people will be much deterred by them; and maybe that's enough. But that might be a hard theory for a court to accept — a strict liability statutory rape law is constitutional only because everyone knows that.
Another is that figuring out the age of one's sexual partner is much easier than figuring out the age of someone in a movie one is distributing or watching. But it's actually not always that easy to figure out a sexual partner's age if the sexual partner is lying about it, for instance by showing a fake driver's license. And in any case the ease of determining the facts in some cases counsels in favor of negligence liability — liability when a person knew or reasonably should have known the sexual partner was underage — rather than strict liability that would apply even if the person acted perfectly reasonably.
There might be another theory — Lawrence repeatedly talks about the importance of sex to creating meaningful relationships. Maybe this means that casual sex between relative strangers doesn't really deserve constitutional protection; it's protected in practice, because it's so hard to draw distinctions between meaningless sex and meaningful sex, but courts shouldn't go out of their way to protect it. And, the theory would go, generally people who don't know how old their sexual partner is don't have a really close relationship to that partner. Thus, strict liability for statutory rape wouldn't really deter meaningful relationships, only casual pick-ups. I don't think courts are likely to buy this, though, because strict liability would end up punishing even meaningful relationships (some girls might consistently lie about their age, even to a serious lover), and because I think courts will be reluctant to generalize about which relationships are likely to be meaningful and which aren't.
Finally, some argue that Lawrence didn't really recognize a true constitutional right to have sex with consenting adults, but just struck down the law on rational basis grounds. I don't think that's quite right, for reasons I mentioned here, and some recent decisions likewise take the view that there's a right to sexual autonomy that's similar in general force to rights to abortion, free speech, and gun ownership. And beyond that, the court decisions barring strict liability in other situation didn't rest on applying strict scrutiny or heightened scrutiny or some such test; they rested simply on the argument that strict scrutiny even for unprotected conduct risks unduly deterring constitutionally protected conduct. And following Lawrence, noncommercial sex with an 18-year-old is indeed constitutionally protected conduct.