Rationale of bicameralism
The principle of bicameralism has a long history. As well as being practised by many states since ancient times, it has also been expounded by the leading philosophers and practising politicians in the course of the development of modern nations.
Bicameralism is in practice necessary to achieve a parliament truly representative of the people. Bicameralism helps to improve and enhance the representative quality of a parliament and to ensure that it is representative in a way in practice not achievable in a unicameral parliament. Modern societies are complex and diverse; no systems of representation are, of themselves, capable of providing a truly representative assembly. Adequate representation of a modern society, with its geographic, social and economic variety, can be realised only by a variety of modes of election. This is best achieved by a bicameral parliament in which each house is constituted by distinctive electoral process. A properly structured bicameral parliament ensures that representation goes beyond winning a simple majority of votes in one election, and encompasses the state of electoral opinion in different phases of development.
Bicameralism is also an assurance that the law-making power is not exercised in an arbitrary manner. Such an assurance is of considerable practical significance in parliaments where the house upon which the ministry relies for its survival is liable to domination by rigidly regimented party majorities.
The rationale of bicameralism is expounded in clearest terms in The Federalist, the famous essays written in 1787-88 by Alexander Hamilton, James Madison and John Jay to explain the Constitution of the United States. This work, which was referred to by the Australian framers, warned that those administering government “may forget their obligations to their constituents, and prove unfaithful to their important trust ... a second branch of the legislative assembly, distinct from, and dividing the power with, a first, must be in all cases a salutary check on the government. It doubles the security to the people, by requiring the concurrence of two distinct bodies in schemes of usurpation or perfidy, where the ambition or corruption of one, would otherwise be sufficient”.
In so arguing The Federalist adopted the French philosopher Montesquieu’s proposition that: “The legislative body being composed of two parts, they check one another by the mutual privilege of rejecting”. Montesquieu was aware of the implications of a single representative body liable to domination by the executive power, a condition observable in many assemblies of the British or Westminster type in which legislative and executive power are combined. He warned that “When the legislative and executive powers are united ... there can be no liberty”.
The Federalist also drew attention to the value of a second, reflective expression of representative opinion. Pointing to “the propensity of all single and numerous assemblies ... to yield to the impulse of sudden and violent passions, and to be seduced by factious leaders, into intemperate and pernicious resolutions”, The Federalist urged the contribution of a second body, less numerous and able “to hold its authority by a tenure of considerable duration”. Such a second body responds to “the necessity of some stable institution in the government”.
The Federalist, in urging the utility of the second opinion, invoked not only arguments drawn from political prudence but also others deriving from the “whole system of human affairs, private as well as public”:
We see it particularly displayed in all the subordinate distributions of power; where the constant aim is to divide and arrange the several offices in such a manner as that each may be a check on the other; that the private interest of every individual, may be a sentinel over the public rights. These inventions of prudence cannot be less requisite in the distribution of the supreme powers of the State.
A philosopher who gave close attention to the question of bicameralism was John Stuart Mill in his great treatise, Consideration on Representative Government (1861). Mill was acutely conscious of the limitations which a house elected on the basis of single member constituencies posed for representation. Mill, writing in a period prior to the rise of the organised political party and party discipline in Parliament, attached little weight to a number of the arguments for bicameralism of the type found in The Federalist. But the principal reason he offered for supporting a Parliament with two Houses is pertinent to any contemporary consideration of this issue:
The consideration which tells most, in my judgment, in favour of two Chambers (and this I do regard as of some moment) is the evil effect produced upon the mind of any holder of power, whether an individual or an assembly, by the consciousness of having only themselves to consult. It is important that no set of persons should, in great affairs, be able, even temporarily, to make their sic volo prevail without asking any one else for his consent. A majority in a single assembly, when it has assumed a permanent character — when composed of the same persons habitually acting together, and always assured of victory in their own House — easily becomes despotic and overweening, if released from the necessity of considering whether its acts will be concurred in by another constituted authority. The same reason which induced the Romans to have two consuls makes it desirable there should be two Chambers: that neither of them may be exposed to the corrupting influence of undivided power, even for the space of a single year. One of the most indispensable requisites in the practical conduct of politics, especially in the management of free institutions, is conciliation: a readiness to compromise; a willingness to concede something to opponents, and to shape good measures so as to be as little offensive as possible to persons of opposite views; and of this salutary habit, the mutual give and take (as it has been called) between two Houses is a perpetual school; useful as such even now, and its utility would probably be even more felt in a more democratic constitution of the Legislature.
Mill thus shared the views of Montesquieu and The Federalist in identifying the virtue of the two Houses as a check on each other.
Bicameralism was addressed from a similar perspective by Walter Bagehot in another classic of political literature, The English Constitution (1867). While not an admirer of the principle of division of power exemplified by the American Constitution, Bagehot recognised the virtue of a second house not easily captured by a disciplined majority:
A formidable sinister interest may always obtain the complete command of a dominant assembly by some chance and for a moment, and it is therefore of great use to have a second chamber of an opposite sort, differently composed, in which that interest in all likelihood will not rule.
The most dangerous of all sinister interests is that of the executive government, because it is the most powerful. It is perfectly possible — it has happened, and will happen again — that the cabinet, being very powerful in the Commons, may inflict minor measures on the nation which the nation did not like, but which it did not understand enough to forbid. If, therefore, a tribunal of revision can be found in which the executive, though powerful, is less powerful, the government will be the better; the retarding chamber will impede minor instances of parliamentary tyranny, though it will not prevent or much impede revolution.
The framers of the Australian Constitution inherited this collective wisdom. When they combined it with their decision that Australia should be a federal nation, they found the case for a strong second chamber irresistible:
There are two essentials — equal representation in the Senate and for that body practically co-ordinate power with the House of Representatives. All those who recognise what are the essentials to a true union will admit these essentials.
We are not here to discuss abstract principles, we are not here to discuss the meaning of words; but I venture to think that no one will dispute the fact that in a federation, properly so called, the federal senate must be a powerful house .... We are to have two houses of parliament each chosen by the same electors .... We are to have, instead of a highly centralised government such as they have in Great Britain, a division of powers....
The Constitution reflected their conclusion that, in order to perform the representative role assigned to it, the Senate, like its United States counterpart, must have the power to veto and to suggest changes to any proposed law. It could not be merely a debating and delaying chamber.