Keep morals out of the law!

There is a recent trend to mix morals and law again. I say again because this used to be the norm and it has been a tedious process to finally separate the two. Going back to putting morals into the law would be a regression of the most horrible kind. Let's start out with some history:

In Hebrew law which is believed to be given by God, morals and religion are obviously not detachable from the law itself. These laws serve as a guideline to a pious life as well as a safeguard of peace in society and are still strictly followed by a lot of Jews all over the world. Many of these laws or rules were taken into Christian doctrine where through the powerful position of the Church in the middle ages they made their way into European ius commune; law that was applicable almost everywhere in Europe. A lot of these laws served as moral guidelines, the church tried to steer the people onto a certain moral path that it, the church, would ultimately profit from. Of course this manipulation has had some positive effects as well. It is undoubtedly true that the christian values of charity are the basis for the modern European "welfare state". But imposing values upon people seems to me to be a bit beside the point. If people only do certain things out of fear for punishment and not because they genuinely believe that what they do is right, society hasn't actually changed for the better and this oppression of free will might actually hinder real thought progression in the minds of people. We are alway keener on an idea if it is our own or we have at least learned to accept it as part of our value system without any imposition from above.

The mixing of morals and law has a strong tradition in Europe, but one of the achievements of the enlightenment period was to do away with that. Immanuel Kant was the first to publicly opine that morals and law should in no way be mixed but regarded as separate entities.
Indeed most people today would agree with this statement. Seeing something as morally wrong or socially unacceptable does not immediately mean that punishment by the state for such an unacceptable behavior should follow.
An example of this is cheating. Whether one is in a marriage or a non-marital relationship, cheating is generally viewed to be socially unacceptable. Yet most people wouldn't want cheating to be punishable by law.

Here I come to another point. Incarceration is the ultima ratio of the state. Penal punishment serves as a last resort if all else has failed to:
1) defend justice against injustice
2) make it clear to the offender that his behavior is unacceptable and won't go unpunished
3) secure the public by taking a dangerous individual off the streets
4) prevent future deeds
5) (most recently) give the victim a sense of its grief being taken seriously by the state

It is thus very important for a society to think hard about which actions to incorporate in their penal catalogue and which not.

In the light of recent events such as demands for a definition of mariage in a certain way in the law and making other acts which only a certain part of the population subjectively finds offensive punishable by law, it has become necessary to outline the progress we have made since the middle ages and make people see the benefits of a strict separation between law and morals.
Only a society which knows this separation can say that its citizens are free.

If we don't want to regress into a society which doesn't know religious freedom, freedom of speech and of opinion, then we need to fight against a moralization of the law.