Laborem Exercens (my high school Latin is rusty, but I translate the title to mean Working) revisits "the social question," which Pope Leo XIII had raised 90 years before in the encyclical Rerum Novarum (literally Of New Things). Pope Leo was responding simultaneously to the excesses of 19th century capitalism and the rising spectres of anarchism, socialism, and communism. John Paul's encyclical updated this thinking to the age of Reagan and Brezhnev.
Fittingly for a spiritual leader (and unlike many Democratic politicians), John Paul did not produce a litany of small policy proposals. Instead, Laborem Exercens re-examined the most basic assumptions of our economic system - assumptions we usually take for granted. The Pope rejected the commoditization of labor, denounced the separation of capital from labor, and even challenged the basis of the property system itself.
The Subjective Dimension of Work
Laborem Exercens' primary distinction is between the objective dimension of work (in which the focus is on the goods being produced, and the worker is merely one of the many factors of production) and its subjective dimension (as one of the fundamental experiences of human life). The importance of this subjective dimension is, in my view, the encyclical's main theme.
[H]uman work has an ethical value of its own, which clearly and directly remains linked to the fact that the one who carries it out is a person, a conscious and free subject ... The sources of the dignity of work are to be sought primarily in the subjective dimension, not in the objective one. [endnote 1]
Economism
The economy, in other words, exists for the sake of people, not people for the sake the economy. Failure to understand this point is an error the Pope called economism.
In the modern period, from the beginning of the industrial age, the Christian truth about work had to oppose the various trends of materialistic and economistic thought.
For certain supporters of such ideas, work was understood and treated as a sort of "merchandise" that the worker - especially the industrial worker - sells to the employer ... [T]he danger of treating work as a special kind of "merchandise" ... always exists, especially when the whole way of looking at the question of economics is marked by the premises of materialistic economism.
If we look at the economy from a purely objective and economistic perspective, we see that the development of technology since the Industrial Revolution has made possible an astronomical increase in production. And so we might think that tools are the primary factor of production, and the workers who wield the tools of secondary importance. We might even put natural resources (like oil or metals) in the second place, and rank workers third or even lower. Consequently, we might award the bulk of production to the owners of the tools and the natural resources, rather than to the workers.
Today, this view often passes for common sense - if it is noticed at all. The Pope not only rejected this assumption, but questioned the whole validity of separating and comparing capital and labor.
We must emphasize and give prominence to the primacy of man in the production process, the primacy of man over things. Everything contained in the concept of capital in the strict sense is only a collection of things. Man, as the subject of work, and independently of the work that he does - man alone is a person. This truth has important and decisive consequences. 
In the light of the above truth we see clearly, first of all, that capital cannot be separated from labour; in no way can labour be opposed to capital or capital to labour, and still less can the actual people behind these concepts be opposed to each other, as will be explained later. A labour system can be right, in the sense of being in conformity with the very essence of the issue, and in the sense of being intrinsically true and also morally legitimate, if in its very basis it overcomes the opposition between labour and capital through an effort at being shaped in accordance with the principle put forward above: the principle of the substantial and real priority of labour.
The Two Inheritances
So what, in the Pope's view, happened to those other two factors of production: tools and natural resources?
Working at any workbench, whether a relatively primitive or an ultramodern one, a man can easily see that through his work he enters into two inheritances: the inheritance of what is given to the whole of humanity in the resources of nature, and the inheritance of what others have already developed on the basis of those resources, primarily by developing technology, that is to say, by producing a whole collection of increasingly perfect instruments for work.
This is a very radical statement: The natural world and the human civilization built on top of it are the common inheritance of humankind, not the sole possession of those who hold deeds and patents. Contrast this with an equally radical opposing view - an excerpt from John Galt's speech in Ayn Rand's novel Atlas Shrugged:
The machine, the frozen form of a living intelligence, is the power that expands the potential of your life by raising the productivity of your time. If you worked as a blacksmith in the mystics' Middle Ages, the whole of your earning capacity would consist of an iron bar produced by your hands in days and days of effort. How many tons of rail do you produce per day if you work for Hank Rearden? Would you dare to claim that the size of your pay check was created solely by your physical labor and that those rails were the product of your muscles? The standard of living of that blacksmith is all that your muscles are worth; the rest is a gift from Hank Rearden.
In Rand's view, only the capitalist is the heir to the technical advances of prior generations. The worker has been disinherited, except for his opportunity to receive a "gift" from his employer. But the Pope views the worker as an equal inheritor to the capitalist, not only of the work of previous generations, but of the Earth itself.
Property
But if the Earth is the common inheritance of everyone, doesn't that bring the whole property system into question? The Pope was well aware of this implication.
In London, not far from one of the many sites that can claim to be the birthplace of modern capitalism, stands the Royal Exchange. Carved above its entrance is the first verse of Psalm 24: "The Earth is the Lord's, and the fullness thereof." Generations of traders have bought and sold the produce of the World under this ironic motto, but John Paul took it seriously.
Christian tradition has never upheld this right [to own property] as absolute and untouchable. On the contrary, it has always understood this right within the broader context of the right common to all to use the goods of the whole of creation: the right to private property is subordinated to the right to common use, to the fact that goods are meant for everyone.
God, in other words, did not create the World solely for the benefit of those who currently hold title to it.
[T]he position of "rigid" capitalism continues to remain unacceptable, namely the position that defends the exclusive right to private ownership of the means of production as an untouchable "dogma" of economic life. The principle of respect for work demands that this right should undergo a constructive revision, both in theory and in practice.
Marxism
Conservatives are probably wondering at this point whether the Church learned anything at all from the 20th century. John Paul's native Poland, after all, was still under the Soviet thumb when Laborem Exercens was published. And yet in these quotes John Paul himself sounds suspiciously like a Marxist from the era of Leo XIII.
Clearly the Pope was conscious of this potential criticism, and went to some length to distance himself from Marxism as well as capitalism. Marx may have sided with the workers against the capitalists, but in objectivizing work and setting labor against capital he repeated the error of economism.
In dialectical materialism too man is not first and foremost the subject of work and the efficient cause of the production process, but continues to be understood and treated, in dependence on what is material, as a kind of "resultant" of the economic or production relations prevailing at a given period.
John Paul also had learned the same lesson that George Orwell put into Animal Farm, that bureaucrats can have all the vices of owners.
[The Church's teaching on ownership] diverges radically from the programme of collectivism as proclaimed by Marxism and put into practice in various countries in the decades following the time of Leo XIII's Encyclical. ... [M]any deeply desired reforms cannot be achieved by an a priori elimination of private ownership of the means of production.
Taking the means of production away from the capitalists and giving it to the commissars, he recognized, does not solve the problem.
This group in authority may carry out its task satisfactorily from the point of view of the priority of labour; but it may also carry it out badly by claiming for itself a monopoly of the administration and disposal of the means of production and not refraining even from offending basic human rights. Thus, merely converting the means of production into State property in the collectivist system is by no means equivalent to "socializing" that property.
Property Subordinated
So if the Pope was not proposing collectivization, and yet he held the private property system suspect, where was he going? The previous quote continues:
We can speak of socializing only when the subject character of society is ensured, that is to say, when on the basis of his work each person is fully entitled to consider himself a part-owner of the great workbench at which he is working with every one else.
The workbench image seems key to the Pope's thinking, key to understanding why the opposition of capital and labor must be a mistake. For how can the tools on the workbench (i.e., capital) be against the worker?
[I]n the Church's teaching, ownership has never been understood in a way that could constitute grounds for social conflict in labour. As mentioned above, property is acquired first of all through work in order that it may serve work. This concerns in a special way ownership of the means of production. Isolating these means as a separate property in order to set it up in the form of "capital" in opposition to "labour" - and even to practice exploitation of labour - is contrary to the very nature of these means and their possession. They cannot be possessed against labour, they cannot even be possessed for possession's sake, because the only legitimate title to their possession - whether in the form of private ownership or in the form of public or collective ownership - is that they should serve labour, and thus, by serving labour, that they should make possible the achievement of the first principle of this order, namely, the universal destination of goods and the right to common use of them.
Within this worldview, private property may still play an instrumental role. Private property is not a moral right, or part of the natural law, but it may (in certain circumstances) be the best social device we can come up with. In particular, a private property system can address the problem of worker alienation by allowing the worker to own some or all of his produce.
[T]he person who works desires not only due remuneration for his work; he also wishes that, within the production process, provision be made for him to be able to know that in his work, even on something that is owned in common, he is working "for himself". This awareness is extinguished within him in a system of excessive bureaucratic centralization, which makes the worker feel that he is just a cog in a huge machine moved from above, that he is for more reasons than one a mere production instrument rather than a true subject of work with an initiative of his own. The Church's teaching has always expressed the strong and deep conviction that man's work concerns not only the economy but also, and especially, personal values. The economic system itself and the production process benefit precisely when these personal values are fully respected. In the mind of Saint Thomas Aquinas, this is the principal reason in favour of private ownership of the means of production. ... If it is to be rational and fruitful, any socialization of the means of production must take this argument into consideration.
An Image and a Challenge
John Paul did not bring Laborem Exercens to an exciting climax with a clarion call to action and a catchy slogan for a 30-second campaign ad. He apparently did not feel the need for such an ending, but I find that I do. Unlike, however, many of the pundits I saw on television during the nine days of mourning, I am unwilling to put my words into the mouth of a dead religious leader. And so in this section, though I write under the inspiration of Laborem Exercens, I write for myself.
Eventually, the Pope did manage to say a few nice things about international law, unions, workers' rights, and worker-ownership plans, but I am left with the impression that John Paul saw macro-economics as an unsolved problem. What stands out in Laborem Exercens, for me at least, is not any particular system or doctrine or policy, but an image and a challenge.
The Great Workbench. The image is the Great Workbench, where all the work of humanity is done. The Great Workbench always has space for one more, and there's always something that needs doing. Tools are waiting there to be used, and they belong to whomever can wield them. You  are not chained to the Great Workbench, but you can take pride in the work you do there and claim some part of it for your own.
John Paul's message, as I receive it, isn't that any particular human Ism will give us the Great Workbench - not capitalism, not socialism, and certainly not communism. It is, instead, a standard by which all the Isms should be judged and found wanting. All have sinned and fall short of the glory of God.
And that, in this age of triumphant capitalism, is a message worth repeating. The Market, no less that the Politburo, is a fallible human institution. Its makings and its judgments should never be taken for granted, and never exempted from criticism.
Justifying property. The challenge is to justify the property system - not just the who-owns-what of it, but also the why-anybody-owns-anything. As property owners - and even the poorest of us owns something - we stand between our fellow humans and their divine inheritance. We stand, in essence, between the Creator and his other creatures. How do we justify that position? Do we stand as mediators that transmit divine grace, or as idols that block it? [2]
To challenge the property system, as John Paul did, is not to deny that it can be justified. Capitalism and private property have won out over rival systems for good reasons, as the experience of the Pope's native Poland undoubtedly made him well aware. But we can't justify the economic system in one way, and then use it in another.
If, for example, we believe (as at some level I do) that the capitalist system in the long run can provide everyone with the opportunity for a better life than they could have under any rival system, then we must carry that promise with us and judge ourselves by it. We cannot justify our appropriation of humanity's inheritance in this manner, and then treat the world's crushing poverty and hopelessness as mere collateral damage. It indicts us. It strikes to the heart of our self-justification.
The Papal Legacy.
This image and this challenge are themselves part of our second inheritance - the one we receive from those who have gone before. In his time at the Great Workbench, Pope John Paul II did more than etch a few conservative thoughts about sex and gender. He left a liberal economic legacy as well. We need to preserve that legacy, and make sure that it isn't forgotten.

[1] All quotations are from the Vatican's own translation
The Pope tended to write sentences of unwieldy length which refer to each other in ways that make them hard to quote concisely -  hence my apparently excessive use of ellipses and bracketing. He also over-used italics. All italics in the quotes are original: I have added none, but I have taken out some of the more distracting ones. In wielding these editorial tools, I have done my best to remain faithful to the spirit of the text, and not to take John Paul's words out of their proper context. The reader is invited (and even urged) to check up on me by reading the encyclical end-to-end.
[2] Christian theology describes two ways of standing between God and humanity - one good, one bad. The good way is to be a mediator. A venerated icon, for example, can mediate meditation and worship. By standing between humanity and God, it makes the presence of God easier to imagine. The bad way is to become an idol, as the icon does when it stops pointing to God and starts replacing God.
Property owners can, and sometimes do, mediate by caring for their property and developing its best use. But they can also be idols - walls that block the flow of divine grace. The property system itself can be an idol. We can worship it and serve its needs, regardless of whether it serves any purpose beyond itself.
One translation of the name of the old-testament idol Baal is "the Owner." We can, through the property system, worship this aspect of Baal and set ourselves up as little Baals. Or not.