Standing order 188 represents basic rules of procedure and provides for the distinction between the formality of the plenary, where senators may speak once on a question or amendment and in reply, and the informality and flexibility of committee of the whole, where multiple contributions are permitted (subject to SO 189(3)).
There are some questions on which no debate is permitted. See SOs 66 (formal motions), 67 (postponements), 75(8) (for the business of the day to be called on, moved during an MPI), 112(1) (first reading of bills other than non-amendable bills), 142(1) (declaration that a bill is urgent), 144(6) (to report progress from committee of the whole), 189(1) (extension of time for a senator to speak), 198(2) (that an objection to a chair’s ruling requires immediate determination), 199(1) (closure of debate), 201 (2) (adjournment of debate) and 203(3) (suspension of senator for disorder).
See SO 190 for the right to speak again on a question to explain a misrepresentation.
For elaboration on the right to speak on amendments and the subsidiary rules laid down by President Baker in 1905, see Odgers’ Australian Senate Practice, 12th edition, pp. 191–92.
The amendments to SO 188 in 1914 and 1937 were technical rather than addressing matters of substance.