*This is a tentative theory and only a beginning.
Proceeding along the method of the Philosopher, let us consider first the simplest and most basic form of the polis, that is the household. In the household, the head or sovereign is both ruler of the people and the owner of the good. Indeed, his ownership provides and sustains his capacity to rule the house and adequately provide for the common good.
A nation is composed of several houses and prior to all other considerations the Sovereign owns all objects in the nation for his concern is the sustenance of the common good. Now private property enters as a dispensation of the Sovereign’s authority over all things under his province. It is provided as necessary for well known reasons and indeed for the sake of the common good. This constitutes the diffusive nature of the common good and consequently authority with respect to external things.
Private property is instituted for the sake of the common good and the goods possessed are still yet ordered to the common good particularly in their use according to the Angelic Doctor. As such, the Sovereign maintains authority over these goods in certain respects and particularly with respect to their use as pertains to the common good.
Hence the free market supposes there to be a conflict between the Sovereign and the market participants wherewith the Sovereign should be gone as much as possible. Yet, it is the domain of the Sovereign to have authority over the behaviors of the men and even in a manner ownership of the things in the market of which men dispense with and use.
There is certainly a tension between the authority of the Sovereign and those possessed of property, but this is a tension of coordination in the common good rather than a conflict particularly with proper goods of individuals.