Countries that have or permit ex post facto (especially criminal) laws.

One of the things that you learn in school in the US is that the US Constitution prohibits so called “ex post facto” laws which purport to punish conduct that was not illegal when it was performed. For example, if Congress or a State Legislature passes a law today saying, “Anyone who operated a motor vehicle within 1000 meters of a public school yesterday is guilty of a misdemeanor and may be punished with up to one year in jail.”, when such conduct was legal under the laws in operation yesterday, that law would be held void if prosecutors attempted to charge people who innocently drove by Memorial High yesterday.

Are there any jurisdictions where ex post facto laws are permitted, or are there jurisdictions that have actually passed ex post facto laws? For example, can Poland pass a law tomorrow saying that it is or was a criminal offense to have used the Internet within the past year? Could New Zealand pass a law saying that any New Zealand citizen who traveled or lived the US during the past five years leading up to the day the law was passed is guilty of a felony?

I’m primarily talking about criminal regulatory laws here. It seems that “three strikes” laws as well as sex offender registration laws have survived challenges based on allegations that they are ex post facto laws.

After Cicero executed citizens without a trial Rome made it a law that whoever did that had to go into exile

Retrospective legislation is fairly common in Australia. Mainly for tax laws and the like. Although the constitution doesn’t seem to prohibit retrospective criminal laws, it sounds like human rights treaties do.

I don’t know if I’d say it’s “Fairly common”, to be fair. Although It’s been a long time since I studied law (and taxation law was never my thing) but I’m pretty sure there’s a whole raft of legal principles (including things like “Natural Justice” and “The Public Interest”, as well as those treaties you mentioned) more or less designed to stop criminal liability ex post facto laws.

Having said that, while I’m sure it’s not unknown for tax laws to be back-dated, my understanding is it would be for administrative things or determining values of items, rather than saying “GST now applies to that car you brought off your uncle 20 years ago”, if that make sense.

Illinois, which is technically part of the USA.

Yes. Like the United Kingdom New Zealand does not have a written constitutioin and follows the principle of parliamentary supremacy. Thus the Parliament of New Zealand can pass any law it wishes and no court can stike it down. Not only could Parliament in theory pass of a law making it illegal do ______ and punich all the people who _____ before it was illegal it could also pass of bill of attainder drawn up of people from the Auckland telephone book declaring them guilty of high treason and sentencing them to death. The Parliament of the UK can do the same thing, though there’s the added complication of assorted EU treaties (then again the only reason those treaties have and standing in British law is because Parliament says soo).

In Australia (and probably other CW countries that do not have express constitional prohibitions) it is in principle possible to create retrospective criminal offences, but politically very unlikely. There are also very strong statutory interpretation principles against a court’s interpreting an enactment, particularly a criminal one, from having retrospective effect in the absence of great clarity in drafting.

That proposition does not apply to tax law, where some famous tax schemes that were legal but manifestly dodgy were prohibited in such a fashion as to allow the govt to claw back tax which had been avoided prior to the enactment of the claw back legislation. I well remember talk of “bottom of the harbour” schemes, and the lurid sounding “wet Slutzkins” and “dry Slutzkins” taking up much time at law school.

Note that I mentioned retrospective enactment of criminal offences. There is a distinction drawn in this area between substantive law and procedural law.
Suppose in 2000, Parliament passed a law against mopery. Clearly enough, it would not have retrospective effect to actions committed in 1988.

But suppose that in 2000, the law that created the offence of mopery also included a provision that one couldn’t be convicted of mopery on the uncorroborated testimony of one witness. Let’s further suppose that in 2005, the corroboration requirement was removed. Tpractical consequence might well be that a person who committed mopery in 2004 but who could not then have been convicted for want of corroboration could be tried in 2006 for his 2004 offence and be convicted. The requirement for corroboration might well be a mere procedural matter, to which the presumption against retroactive effect does not apply.

Fascinatingly, the High Court of Australia (local equivalent of SCOTUS) decided a case two days ago touching upon this general issue.

In 1963, a man rapes his wife. At that time the common law was believed to be that rape did not encompass a case where the victim was the wife of the perpetrator. In 1991, the High Court overturned that archaic rule. In its ruling the other day, the High Court concluded that the man could now be convicted of the 1963 rape.

That law did not criminalize anything. Why is it even in this discussion?

It’s not exactly what the OP is looking for, but I think that basically the same problem exists when criminal laws are vague and/or are selectively enforced.

For instance, the crime of blasphemy is still on the books in Germany (§ 166 of the German penal code). It had, however, been renamed and is called “insult of a religion” these days. For the longest time, nobody took this very seriously, it was more or less seen as a curiosity and a relict of the dark ages.

Hardly anybody had been prosecuted, let alone tried or even convicted for this crime for ages until recently when a man who had made a crude practical joke involving the Quran was given a suspended sentence for “insulting a religion”, the religion in question being Islam.

So far as I can tell, the recent case involving Centrelink benefits is an instance of such. The story here is the High Court ruled a woman had not committed an offense by omission of reporting, and so the parliament amended the Act to make such an offense, and the amended Act applys retrospectively.

If I’m reading this correctly, this law is being used in a criminal trial for a crime that occurred before the law was passed. It certainly seems relevant.

It’s not a “law” in the sense of legislation passed by a governmental body; it’s an exception to the longstanding common law rule against hearsay. As was pointed out by Noel Prosequi, that’s a procedural rule adopted by trial courts, as a function of their statutory ability to control their own process and apply or adapt the existing rules of evidence.

Further, it has nothing to do with “criminalizing” prior conduct. It simply makes an exception to the hearsay rule (which broadly defined requires the person who asserts something to say it directly to the court, not “Well, Dave told me Marty was the killer.” - that would have to asserted by Dave), and allows evidence to be provided by a party who is not available to testify - in this particular case because the witness is missing presumed dead. There is a similar hearsay exception in Canada.

The court then would caution the jury (or itself) that such evidence, while necessary in this instance, does not automatically make it reliable.

Technically, the Nürnberg trials were based on ex-post-facto laws since what those bastards did was legal under the laws in Germany when they were performed. One can argue that what they did was illegal under common law or something. I am certainly not making a brief for them, but it was an ex-post-facto prosecution. Nowadays there are “international laws” but many countries, including AFAIK the US, do not recognize. It certainly puts a patina of legitimacy on such things as the recent prosecution of Charles Taylor.

[hijack] That is not hearsay, that is original evidence as the witness is only repeating what Marty told him. If the witness states that Marty was the killer THAT would be hearsay

If that’s the case in the U.S., then I assume that is not generally allowed either, as it would be an easy loophole, and thus there would be no need for an exception.

Or perhaps your jurisdiction defines the term differently.

My jurisdiction uses the common law definition. And at common law you are allowed to repeat what you yourself heard (perceived as we lawyers call it). The example given above had one person repeating what another told him. It would be hearsay if it was adduced to show the truth of the contents of what the second person told the first person not hearsay as to the mere fact of so telling. In other words, it cannot be used to show that Marty was the killer, it can be used to show that xyz believed that he was. Whether that is damming or irrelevant depends on the case itself.

Well - in the US, CERCLA (more commonly Superfund) is environmental legislation that seems to be ex post facto - it often imposes cleanup requirements on polluters for actions undertaken prior to the passing of the legislation. Apparently, it’s not considered unconstitutional because . . . . well, I’m not really sure, but this guy seems confident:

Well, you could argue that the pollution is a condition which continues into the present, not simply an incident which is in the past. Not that I necessarily agree with this interpretation, but it seems reasonable.

OTOH, nobody really knows why the IRS can get away with acting like the KGB, and why Due Process doesn’t apply to them. Sometimes, the law simply has blind spots.