This arises from a quick post on Metamorphoses the other day which, after making allowance for some Hayekian skepticism regarding the phrase "social justice", suggested that the concept might be interpreted in a broader sense than the usual blanket rationale for left-liberal state confiscations and distributions. Borrowing from another post, I called this broader context a "just society". (As an aside, I'll just note that in Canada this phrase has unfortunate associations with a charismatic but controversial former Prime Minister -- please, no snickering at the notion of a "charismatic Canadian" -- and then I'll ignore those associations.)
Now it's plausible, and interesting, to think of those two notions as strongly related, if not synonymous -- wouldn't "social justice" prevail, after all, in a "just society"? And it's also enjoyable to see how, as the original article relating to the Tea Party movement pointed out, the latter notion either forces an enlargement of the meaning of "social justice", or forces the partisan narrowness of the concept out into the open. But it's also possible, and maybe instructive, to consider the two notions as distinct in an important way. The notion of justice that's contained in the phrase "social justice" is the notion of a just end or condition of society, in which everyone receives exactly what's due him or her, and is maintained in this condition. The notion contained in the phrase "just society", on the other hand, is the notion of a just structure or framework for society, within which everyone is free to act as they see fit and obtain what they're able and willing to.
This is a familiar enough distinction, perhaps, but laying out the alternatives in this way I think helps make clear some of the oddities and difficulties inherent in the "social justice" view. First, how are we to determine just what is "due" to a particular individual, or even to some grouping of individuals? Second, even if we could determine this, how are we to ensure that individuals actually get what they're due, and no more than they're due? Third, even if we can make this sort of "just" distribution once, how are we going to ensure that everything stays just, as people go about their daily lives? It would certainly help if we had a divine perch from which to look down on and into the lives of individuals to determine what was each their due, and then a divine power to dispense or distribute goods like Santa Claus at Christmas, as well as to reach into their lives on an ongoing basis so as to maintain this just distribution. But, lacking that, "social justice" proponents tend to fall back on the simple notion of dividing the available goods equally, regardless of merit, character, motive, choice, etc., -- not to mention right -- and relying on the tax man and other state bureaucrats in lieu of God to enforce this rough state of "justice". In the real world, of course, few such proponents any longer think it's possible to impose such an absolute egalitarianism -- there aren't many real communists left -- but that simply means, in practice, that they'll always view any actual condition of any actual society as requiring ever more substantive equality to be more "socially just".
All of which, though, should make it clear that the notion of "social justice" as some sort of just end state or condition of human society is not just a mirage, the pursuit of which is folly -- it's also wrong, or unjust in itself. We're not God or gods, nor are our political representatives, nor the bureaucrats they appoint, and the pretence that anyone can determine what is justly due everyone is nonsensical and arrogant. The attempt to enforce a crude version of that kind of "justice" through an endless campaign of egalitarianism is manifestly unjust.
"Justice", however, as a form or structure rather than as a substantive condition is quite another matter. In this sense, justice consists of a set of fair or just rules for behavior, within the limits of which the varying human situations are all equally just, regardless of condition. This doesn't mean that we should do nothing about such varying conditions -- justice isn't the only human virtue, after all, but is only one among such others as mercy, compassion, and love. But, unlike the way in which "social justice" often subverts virtue, the "just society" is one that provides a foundation and structure for the exercise of virtue.