From the beginning of the article:
Two qualities I have always admired in the work of Mogens Hansen are his willingness to question old assumptions and his thoroughness in collecting evidence. These two qualities are nowhere more conspicuous than in an article modestly titled “Two Notes on Demosthenes’ Symbouleutic Speeches”. In the second of these two notes Hansen examined the view “often stated, but never substantiated that Demosthenes virtually initiated the custom of publishing speeches delivered in the assembly”. Hansen observed that at most 19 out of the 150 preserved speeches of the Attic orators were delivered in the assembly. These include Lysias 28 and 34, Andokides’ De Reditu and De Pace, Demosthenes 1-10 & 13-17. Three of these, Hansen pointed out, are not true demegoriai, that is, symbouleutic speeches: Lysias 28 was delivered during an eisangelia and thus falls into the category of forensic oratory; Lysias 34 is most likely a political pamphlet; Dionysios says that it was never delivered; and Andokides’ De Reditu is strictly speaking a petition, not a symbouleutic speech. With characteristic thoroughness Hansen then searched through the testimonia and fragments of the lost orations for evidence of other symbouleutic speeches. He found very little: there is slender evidence for one symbouleutic speech by Andokides, two by Hypereides, and one that was attributed by some to Deinarchos and by others to Demosthenes. This led Hansen to modify the traditional view that Demosthenes was the first to publish symbouleutic speeches delivered in the Assembly. “It seems more correct”, he concluded, “to say that Demosthenes was exceptional in publishing several of the speeches he delivered in the assembly”.
The only apparent exception to the traditional view was the speech De Pace attributed to Andokides. There is no other extant symbouleutic speech that was published before Demosthenes; there are two brief references to a symbouleutic speech by Andokides, but these come from late sources and give no indication where the speech was delivered. It is odd that Hansen did not examine this one firm exception more closely since Harpokration doubted the authenticity of the De Pace and Dionysios declared it spurious.