Deconstructionism is what Jacques Derrida (a now deceased French-Jewish postmodernist) uses to describe his method of studying literature. According to Derrida, pieces of literary production is aimed at representing reality. The problem with this is that representation cannot fully encompass the reality which it is aimed at representing. Hence, it does and does not represent reality. That means that all representation is a contradiction. It is, a yes and a no. The term that Derrida uses to describe this is "differance."
One example that the Derrida uses of this (which I read in a seminar in college) is the Book of Revelation. The Greek title of the book is "Apocalypse"- which means to unveil. But is it really an unveiling? What Derrida points out is that it is meant to unveil the end. But since the end hasn't really happened yet, it still remains somewhat veiled. Therefore, claims Derrida, the work is a contradiction. It claims to unveil and then it really doesn't. What it does is unveil, and then defers the truth that it is supposed to represent until a later date. Ultimately, all writing does this. It may be a partially correct representation, but it is only partial. Truth is in the whole (similar to Heidegger) and since the whole never arrives, truth is infinitely deferred.
How is one to respond to this as a Lutheran Christian? One Reformed Christian, Kevin Vanhoozer has made some interesting observations. Though Derrida was an Atheist during his life time (he obviously no longer is now that he has passed on), he was also Jewish. There is, argues Vanhoozer, something distinctively Jewish about Deconstructionism. The infinite interplay of signifiers mirrors the endless and contradictory results of Rabbinical hermeneutics. Lacking the Messiah and his final interpretation of the Word, the Rabbis were free to defer meaning in their interpretations infinitely until the Yom Yahweh.
I think this also brings out a point that Peter Leithart has made in his book on postmodernism. Postmodernism is not relativism, the way that many conservative Christians often characterize it. Really, it would be better to call it "provisionalism." There is no truth that is final. There may be truth in our representation, but the final representation is deferred forever and ever.
This brings me to the Lutheran response. One keen observation that Oswald Bayer has made is that there is a connection between Luther's so-called "Reformation breakthrough" and his doctrine of the communication attributions. Just as the humanity of Jesus possesses the fullness of divine glory (genus majestaticum), the Word of the gospel is the very presence of God. It is also the final verdict of God on the sinner. Hence, according to Bayer, Luther's great discover was that the words of the priest "I absolve you" are identical with God's own action.
What this suggests is that for Luther and Lutheran Christians, there can be no infinite deferment in the manner of Derrida. The man Jesus is in fact the very presence of God (genus majestaticum) and therefore his word (validated by his resurrection) is the final eschatological verdict on the sinner. The signified is present in, under, and with the signifier. This is why Jesus emphasized his role as the Son of Man. For Second Temple Jews, the Son of Man was a cosmic judge that would come at the end of time. Jesus revealed himself as the Son of Man who's verdict was already a present reality to sinners. He gave this same Word of justification to the Church and thereby the proclamation of the Church lacks any deferment in its truth. This is one of the reasons why the Trent's position that the sinner can only be certain of his final vindication in a provisional sense is so utterly wrong. The Son of Man's verdict is already present and complete in Word and sacrament. There can be no uncertainty about it.