Numbers of uses of words in a computerized corpus of speeches, manifestos, Green Papers and what-not are counted up. We are enlightened about the populist use of the glottal stop. Also about Blair's poetic, this being discernible in his recollection of Gower St. transfigured, as it was by the people when he was on the way to Buckingham Palace after the election. But we are not to be so mundane or merely English as to take discourse to consist in a stretch of speaking or writing. Discourse is something constructed in discourse mundanely understood.
Discourse can have discourse in it.
It is, or it has to do with, a representation or vision of the world as it is and should be. Government is not only in but really is discourse. Late in the book it is only moderately reassuring to hear that when an army's artillery levels a village that is not just discourse. It is pretty easy to put up with this advanced thinking because the book is also cogent. There are excellent reflections on Blair's rhetoric in his sincere and perfect words to her sons on the death of Diana.