the senate being the house of review must be able to return appropriation bills to the house of reps. this is a vital function
it must have the ability to recommend amendments to these bills thereby making sure of the independence of the senate. appropriation bills may not originate in the senate but it may force the house of reps to change the proposed bill.
the inclusion of this (sec 53, 57) in the constitution is from 3 principles -
1 that the house of reps is solely responsible for the form of the money bills to which the section relates
2 that the senate may request alterations in any such bill
3 that if such request is not complied with the senate must take the full responsinbility of accepting or rejecting the bill as it stands
if the senate is to have the power of assent it musrt also have the power of veto
and under sec57 all of the required triggers for a double dissolution were reached. the only time i ever hear of anybody disputing the ability of the senate to reject supply or that the senate should have this power retracted is in relation to the alp's great god, gough.
http://www.ozpolitics.info/guide/topics/dismissal/ gives an excellent precise of the events leading up to the dismissal and a few breif notes on the powers then exercised.
the whole crux of the dismaissal was that whitlam along with his fellow travellers, oconnor and the russian trained and sympathetic murphy and one other were acting illegally in concert to borrow a then enormous sum of money of which they were all to get a very large sum of money as a fee. god help australia if they came thro with the money
