I treat reproductive human cloning as one of such things. Current technology is far from a success, and reproductive human cloning does not seem to be a near future possibility. So, any law against cloning seems to be a currently useless thing, like it's useless to promise someone not to punch their imaginary friends.
What's the point of such laws then? Why are they adopted?
As I see it, there are fundamentally three reasons a person would outlaw an action that is currently impossible:
If you refuse to outlaw an immoral act until it can be shown to be possible, you run the risk that a person can commit this act before it has been made illegal. Essentially, the legislative body doesn't want to risk the law falling behind the science.
The theory behind this is that if an action is illegal, there is less of a risk that a person will work out how to do it. Obviously, this reasoning can be taken to ridiculous levels but if there exists a credible possibility (in cloning, mammalian cloning has been possible for a long while) it can make sense to outlaw an act to dissuade people from working out how to do it.
The law is not always about practicality – it can also be a way for a society to codify its cultural and moral beliefs. In this case, even if it seems unlikely that an actual human cloning could take place, it is a clear sign to the world that a specific nation sees the act as fundamentally wrong.
So, any law against cloning seems to be a currently useless thing, like it's useless to promise someone not to punch their imaginary friends.
The simple difference is that their imaginary friends will never exist.
Waiting until something is actually possible to make it illegal means that it is likely to occur, especially when you consider the time it takes to make a Bill law. Therefore it is far more sensible to make something you would not like to occur illegal as soon as it is plausible in the short to medium term.
A fairly large one is that
You brought up cloning as an example so let's run with that. This article goes over why we can't clone humans yet and notes this rather large show-stopper
[G]iven the science we have now, it would still require a significant number of failed human pregnancies, so many that it’s hard to imagine ethics committees allowing the research to happen. Stem cell biologist Yi Zhang, whose work solved the blocked gene problem, pointed out to Tech Review that the process of creating just two long-tailed macaque monkeys required 63 surrogate mothers and 417 eggs, all of which resulted in just six pregnancies.
There's several major ethical considerations here
Harvesting eggs. Too often the risks are glossed over but there are some serious downsides
Unlike the process men undergo to donate sperm, the preparation and procedure involved in egg donation require a longer-term commitment — a woman’s body is hormonally altered through the process, and she undergoes surgery.
I’d like to see ads note that fact, along with the known risks of egg donation. The ads don’t mention ovarian hyperstimulation syndrome (OHSS), a condition that causes the ovaries to swell and become painful in about one-fourth of women who use injectable fertility drugs. (OHSS generally goes away after a week or so, but in severe cases it can cause rapid weight gain, abdominal pain, vomiting and shortness of breath.)
Nor do they mention that the surgery to remove the eggs can sometimes lead to complications, including cramping, bleeding and infection.
Surrogacy and surrounding risks. As noted above, monkey surrogacy needed 63 surrogates to undergo as many as 417 implant attempts just to get 6 viable pregnancies. On top of that, Dolly the sheep (first cloned animal) was the only normal sheep of the entire experiment to survive and develop normally. Doing this with humans may result in the creation of lots of deformed children, not to mention the risks to the women doing this (lots of miscarriages, plus the physical and emotional toll of that).
Who owns the result? Unlike In-Vitro Fertilization with surrogacy, you've got a genetically engineered individual whose existence is due to the hard work of someone else. Can a company own a person that they helped create?
Unauthorized cloning. What if someone were to clone a famous person? Does the cloned person have any right to destroy the unauthorized clone? What about removing the clone from the parent(s) they have?
There's a lot of thorny issues to hammer out. A pre-emptive law making the underlying act illegal bypasses them all.
One factor not yet mentioned in the other answers is that legislators do not draft laws purely for the effects they will have when implemented, but also for the effect which announcing them as policy will have on voters.
If I know that my key demographics believe strongly in something, regardless of the reality of the situation, then I would want to announce policies which align with those beliefs. If the counter position is weakly held, then this will often translate into law with very little active effort.
To use your example, many people believe that cloning is the worst of scientists "playing god", especially when it comes to human cloning. In an attempt to win votes, Politician 1 announces their objection to human cloning during a campaign. Politician 2 looks at their voter demographics and finds that there is no strong feeling either way, so they fight Politician 1 on other points, not on cloning. If Politician 1 wins, then anti-cloning legislation is easy to implement, due to the lack of strong resistance, and can be used to show that they keep their campaign promises.
In your cited case, to forestall further research being put into the subject.
If the activity is deemed illegal, then most research organizations that might work on this are excluded, and progress is greatly diminished.
That won't stop someone or some organization from pursuing human cloning, but it will insure that the research centers of the EU and US won't be contributing to that.
Another fantastic example of this phenomena comes from China. It is illegal to reincarnate there! Why would an officially atheist government pass such a law?
Tibet. The Dalai Lama, the religious and cultural leader of Tibet, is said to be reincarnated. When the current Dalai Lama dies and "reincarnates", whoever claims to be the new Dalai Lama can be charged with a crime.
(When looking for a source, it appears it is a bit more complicated and you can actually apply for permission to reincarnate from the government?) https://en.wikipedia.org/wiki/State_Religious_Affairs_Bureau_Order_No._5
There's a difference between something that's physically impossible and something that's technologically impossible.
If something is physically impossible, there's no need to prohibit it, because no one will ever violate it. Although if there's likely danger from trying it, you might want to prohibit attempts, to protect the subjects of the experiments from that risk.
But if something is technologically impossible at the current time, you may be able to envision scientists and engineers overcoming those limits in time. If you believe that you won't want to allow it when it becomes possible, it makes sense to pass the law against it now, rather than waiting until after the fact. This might be especially true if you're concerned that the party in power when it becomes possible would have a different view, and wouldn't prohibit it then.
It might also be easier to pass the law now. Since no one has skin in the game yet, there's likely to be weaker opposition to it. There won't be any lobbying groups, for instance.
There are some excellent answers above but sometimes using a more extreme example helps clarify the issue so instead of human cloning, let's take the example of a human/animal hybrid. As far as we know, no one has created a full human/animal hybrid with human level intelligence but just like human cloning, it is likely possible. Also, just like with human cloning, there are already numerous laws outlawing and regulating it. One of the main reasons is the ethical problems with having something that is not human but no longer what we would consider an animal either. Should a highly intelligent mouse or monkey be allowed to reproduce, vote, etc...? It's easier to prevent it from happening in the first place than to have to deal with what happens after it exists.
Some action being illegal before it's possible tends to slow or stifle it becoming possible in the first place. If it is a theoretical possibility, and the only thing in the way is regulation, then any work toward this illegal end is dubious at best and could possible bring legal action on it's own. The regulation is intended to keep the possibility of this from becoming practical and real. If there was a regulation like "It's illegal to accelerate to a speed higher than C", that would be ridiculous because it's not even theoretically possible. This probably hasn't stopped the Vogons from incorporating such a regulation in their Time-Space Velocity Act, however.
While cloning a human hasn't yet been done, it's definitely not impossible. If fact, the necessary technology to start a human cloning experiment is already available. I'm not saying that such an experiment is guaranteed to be a success, but I wouldn't exclude this possibility either. Compare this with a manned flight to Mars: nobody's been to Mars yet, but would you call flying to Mars "impossible"?
You don't refer to a specific law, but I'd hazard a guess that such laws forbid the very attempt to clone a human for a reproductive purpose, regardless of whether the attempt succeeds or not.
In essence, the law is there to prevent people from doing something they already can do, like investing in human cloning technologies. Passing such a law when the reproductive cloning becomes available would be too late: by then you'll have people who invested their money in the cloning business, and laws which deliberately drive people out of business is a sure way for a country to create a poor economic climate for years to come.
Another aspect is to not upset voters and citizens. If I know that cloning or any other thing I might think of is illegal I won't go out and find investors and employees to create my business.
If I end up spending millions of dollars and hours in this endeavor and then somehow succeed with what everyone thought was impossible. Then the investors and everyone expects to gain a lot of money on it. But then suddenly they pass a law that it is illegal, then they will understandably be upset. This happens today with legislation still, but if you can be upfront with it then the better.
