...it is only in substantially free societies that men and women can be morally good.
That statement from the article is wrong in one sense. It carries an implication that one can't be morally good unless there is a politically clear path towards successful actions arising from morality.
Here is a quick example: A highly moral man is wrongly jailed. He has almost no liberty at all. But he will still attempt, within the extremely limited range of actions inside of jail, to live by his ethical standards. Morality is first a set of beliefs that are chosen, and then against which external circumstances are evalutated - actions are then chosen after evaluations and their success or failure is yet another aspect.
It is very true that it requires a substantially free country to protect a substantial range of actions for its citizens. Governments, by their nature, prohibit and consfiscate - those are their two primary functions. If they prohibit a great many actions that are morally good, that is, of course a problem. But morality is more fundamental than liberty.
The title to Professor Machan's article, if taken literally, mis-states the relationship between Liberty and Morality. It could have been "Liberty is Necessary for MAXIMIZING Moral Actions" - or, "Liberty is Necessary for PROTECTION of Moral Actions" - or, "Liberty is Necessary for Many Moral Actions to Succeed". (all very boring)
But this article, which might not have the best title, does an excellent job of examining the relation between morality and coercive governments in other ways.
Professor Machan made the point that being 'good' because you were forced to, is a radically different thing from being good because you chose to. That's a valid point with important ramifications.
And it is a particularly important point to make in our society where progressives are trying to use the government to force us to be good in almost every single area of our lives. They tell us that to be good requires this kind of light bulb, that kind of toilet, this kind of tax, that kind of license, helmets for our heads, only politically correct thoughts for our minds, labels on our clothes and food, safety stickers on ladders, no trigger words from our mouths, and it goes on and on and on.
He also shoots down the weak argument of the moral skeptics who attempt to support liberty by saying liberty is required since no one can know what is really good or bad or right or wrong. (And, I'd add, that the arguments of the relativists are similarly flawed.)
He made an argument against those who would choose elites to command us... as if these elites had an inside knowledge of what is good, bad, right and wrong that the rest of us don't.
There is currently a cartoon being published where the passengers in a plane are protesting the "insider" status of the pilots and demanding that an outsider, "one of us" fly the plane. That is the progressive elite's view of Trump's election where they see Trump as an outsider who is unqualified which illustrates the progressive's belief that they, as elites, hold special knowledge and should be in power. And then they can command into existence the morally good state of things. And it serves to comfort themselves by refusing to acknowledge that more and more people are rejecting the very idea of elitism in government.
Going back to the main issue. Morality comes to the individual far before they are even old enough to conceptualize it explicitly. They can choose to act in ways that are deemed good. This might include choosing not to cut in line, not to hit their siblings, and this applies even where it's not against the law, or even if they can 'get away with it'.
As children we were instructed, and even commanded, to do the right thing. We were taught. As adults we engage in that mental process to establish the moral weight (by whatever standard and whatever psychological quirks unique to the individual) a given choice will have. There could never be a regime so totalitarian as to encroach on this process totally - it would bring about coma-like results in all people, all the time.
Professor Machan made other excellent points: Coersion will have the effect of undermining personal responsibility. That virtue will not arise out of forced charity. That paternalistic governments are really not concerned with helping and protecting but rather they are power-seeking with morality as their excuse.
So, I disagree with the article's title - as worded - for the reasons stated, but I applaud the many excellent points that were made along the way. For me, the heart of the article was that the relationship between morality and politics favors those who seek liberty and that the exercise of morality is bettered when liberty exists and that those who claim moral grounds for reducing liberty are wrong and that many are simple power-seekers hiding behind false claims of promoting moral values.