The Plagiarism of orators is the art, or an ingenious and easy mode, which some adroitly employ to change, or disguise, all sorts of speeches of their own composition, or that of other authors, for their pleasure, or their utility; in such a manner that it becomes impossible even for the author himself to recognise his own work, his own genius, and his own style, so skilfully shall the whole be disguised.
If someone tells you that George Bush is not the 43rd president of the United States, they might be engaged in wishful thinking, or denial, but if they make that claim, it's either true or false! And you can assess that, regardless of whether there's an omniscient narrator, or an unreliable narrator, or it's shot in vérité, or it's manipulated, it's agitprop, whatever! It makes no difference! It's a style!