That is something which one cannot do, as we are now to believe — though "morality" is taken to mean "sexual morality." The claim is, of course, provably false. We do almost nothing but legislate morality: we pass laws which at the best reflect our customs and folkways, to the extent that we have any folkways remaining, and when we legislate we do so based upon a shared sense regarding what a good society looks like, and even what it means to raise good and noble individuals.
The great counterexample, one that is always put on display, is Prohibition. It did not stop people from drinking. It only stopped people from drinking legally. If people were going to drink, they were going to do so one way or another. Such is the argument, anyway.
That was not the argument of the women's temperance leagues, however. They pointed, no doubt with some exaggeration, to the social harm caused by drunkenness, the men who blew their salaries on drink, the wives and children beaten up, the families in disarray. It is no accident that the first thing that the new female electorate did, upon receiving the franchise, was to use federal authority to override local authority and local customs, to restrain the bad behavior of men.
Now, I have no love for the idea of Prohibition. There were all kinds of things wrong with the law. I don't think the federal government has any business bossing around states and municipalities on what is eminently a local matter, involving local ways of life. Wouldn't it have been a lot easier, for example, to arrest men who were drunk in public, and fine the owners of taverns who kept serving them long after they were clearly intoxicated? Also, the amendment outlawed something which was, in itself, not an evil, and in fact was rather a positive (though minor) good. That is, there's nothing wrong with taking a drink, and a glass of beer or "wine that gladdens the heart" has long been a part of man's conviviality and feasting. Then there was the unintended consequence of the spree of crime based on the sale of bootleg alcohol. Finally, there was something waspish about it all, as it coincided nicely with the eugenic concern that the nation was being overrun with "lesser stock," all those Mediterranean Catholics.
So I think that what Herbert Hoover called "a noble experiment" was ill-conceived. Did it work? That is, did it actually decrease the number of people who got drunk? A related question might be, "Did Carry Nation's crusade work?" Or, "Did the Knights of Father Mathew achieve any part of their aims?" Closer to home, has the crusade of Mothers Against Drunk Driving, a crusade that was both legal and moral, worked? Are there fewer people driving drunk than there used to be?
I believe that there is ample evidence to show that the MADD crusade has been victorious, almost as far as any such moral crusade in an imperfect world can be. And I find it prima facie absurd to suppose that similar social movements in the past were utterly ineffectual. That is, the way out is to argue that only such people as would not have been drunks anyway would be moved to join the Knights of Father Mathew. If that were the case, though, then it would make no sense for any of us at any time to attempt to persuade our fellows (and ourselves!) to change. But history is full of examples of moral movements wherein people turn themselves about, for the better or, alas, for the worse. Gertrude Himmelfarb has written about the concerted efforts of nineteenth century reformers and moralists (yes, that was once not an evil word) to clean up the debauchery of the previous era, efforts that were in large part successful. As late as the presidency of that enigmatic duelist Andrew Jackson, men defended their "honor" against an offender with pistols; that is how Aaron Burr slew Alexander Hamilton. But dueling fell to an increasingly popular moral animus against it. In the Middle Ages, common peasants and townsmen banded together, with the assistance of the Church, to curb the violence of noblemen. Such movements as The Peace of God and The Truce of God were not effective immediately and everywhere, but they did work as part of a larger social expectation, morally based, that violence must not simply be a way of aristocratic life, and in these regards the late Renaissance nation-states represented a distinct moral regression, enabled in part by gunpowder, but also by the view of the state as a kind of god on earth. No doubt William Wilberforce was derided in his day as a meddling moralist, and the apologists of slavery in the American south were quick to argue that the Negroes would have been treated worse in Africa, and that the factory owners in the North abused their workers in their turn. But the outlawing of slavery eventually achieved more than just the practical outcome, that of freeing the slaves. It achieved a moral outcome, as people came to be persuaded that the chattel trading in human beings was a terrible evil. Indeed, one of the arguments of the abolitionists was precisely that the existence of slavery had a morally vitiating effect upon the owners; that people who might otherwise be decent enough were led by the permission to own slaves to become callous, irresponsible, cruel, or debauched.
So, then, did Prohibition actually lower the level of drunkenness in America? Yes, it did. The evidence is inescapable. Take a look at actuarial tables drawn up before and after Prohibition, and note the number of people who died of alcohol-related causes. You will find, for example, a sudden and very sharp drop in deaths caused by cirrhosis of the liver. Not only that, but the incidence of such deaths remained low all throughout the Prohibition years, even though some of them coincided with the miserable time of the Great Depression. Prohibition, whatever else we can say about it, actually did achieve the primary end for which it was passed. Did it mean that nobody got drunk? Of course not. Did it mean that drunkenness became far less common, far less of a way of life? Of course it did. Does that mean that it was a good law? No, it was a well-intended bad law. Is it evidence that one cannot legislate morality? Quite the reverse. Is it evidence that one should not legislate morality? No, not at all. The question is, what to legislate about, where, how, to what end, and with what possible unintended effects.