I'm not doing that-I'm pointing out that a society's desires and beliefs aren't the ultimate standard of what is or should be legal.
I beg to differ. A society's
"desires and beliefs" as you put it are indeed the ultimate standard for what
*is* legal when they are expressed through the legislative process in the USA; with the caveat I continue to mention, which is that such laws must still pass Constitutional muster if challenged via the judiciary branch.
As to what
"should be legal," that's a different kettle of fish altogether. Now we veer into the realm of morals, social standards, the current zeitgeist, and so on.
You have brought up the issue of miscegenation, so let's visit that for a moment. In many US states, it was formerly illegal for people of different races to marry. I will stipulate that such laws were unequivocally immoral, wrong, bad, and evil. Please understand that I do not defend them in any way except one; their legality at the time. I do not equate 'lawful' with 'right' in this sense.
It is clear that historically, many of the white citizens of some US states wished to deny certain rights to black citizens, and especially to protect themselves from what they felt were the dangers of interracial marriage (not all miscegenation laws were about blacks and whites; California had a law forbidding Asian and white marriages until 1948). Did they have the legal right to enact such laws? Yes, unless such laws contravened civil rights defined either in their own state Constitutions or the Constitution of the USA as applied to the states via the 14th Amendment's 'incorporation clause' (which did not start until the 1890's).
As we know, Loving v Virginia ended all legal anti-miscegenation laws in the USA, based on the fact that such laws violated both the Due Process and Equal Protection clauses of the Constitution.
That does not mean that such laws were illegal retroactively. It means that an injustice was done, and it was rectified to the extent that it could be in law.
It did not argue that such laws were immoral or evil. It argued that they violated protected and defined civil rights.
So, were anti-miscegenation laws 'wrong'? Of course they were; morally I would absolutely agree they were wrong, they were always wrong. Were they illegal? Not at the time, but they were found to be later when the Supreme Court finally granted cert to such a case.
Getting back to drugs; societies have the right to order their society as they wish, according to their own standards. Those standards do not have to pass any moral test of goodness or badness to be lawful, although society may choose to enact rules for moral reasons if they wish. Morality may inform a society what it *should* do, but it does not inform a society what it *must* do. If society wishes heroin to remain illegal, and passes laws to ban it, society may do so legally, despite protestations of the relative safety of heroin or the claimed right of a person to ingest whatever substance they wish (until such a civil right is found to exist in the Constitution).
Our own society has placed restrictions upon itself, however; it is not
just the zeitgeist that rules. Laws must also pass muster with respect to the civil rights protected by the Constitution and the limits placed on federal authority. No law in the USA has ever been overturned in court because it is morally wrong; its wrongness or rightness doesn't enter into it (juror nullification may be an exception).