Until 1948 the Australian Senate used a first past the post (FPTP) block voting electoral system. If a party got the largest number of votes in the State, then it got all the Senate seats. This often lead to one-sided outcomes that did not reflect the political diversity of the electorate.

The Chifley government was concerned about Labor's long term prospects in the Senate and added proportional representation to the voting process in an effort to entrench their majority. In addition they expanded the number of Senators. Like all electoral changes in Australia to entrench incumbents, it failed. Labor has not held a majority in the Senate since 1951.

Inside; graphs comparing the two voting systems and a poll on which is better for the senate.

First Past The Post

FPTP is a simple voting system . Every elector gets one vote and casts it for their candidate of choice. In a single member district, the candidate with the highest number of votes wins the seat. It is possible that the candidate will win the seat without a majority of support, potentially reducing their popular legitimacy.

In multi-member districts, the use of FPTP block voting can lead to super-majorities for the party, despite having less than fifty percent of the vote. For instance in the 1946 Senate election, Labor ended up with ninety-one percent of the seats, from fifty-two percent of the vote . These wild jumps from super-majority to super-majority characterized the early Australian Senate.

The Australian Senate was intended to be a minority house of review that would represent the states, and stop provincial tyranny from Canberra. This has never occurred, the Senate has never divided across State lines. The parties have leveraged absolute party discipline in the Senate. This graph shows the seats by voting block. Blue for Labor, Red for Liberal/UAP/National and yellow for independent.

The Free Traders are yellow as they did not enter into a coalition with either the Protectionists or Labor. Until the disappearance of the Free Traders, the Protectionists and Labor largely voted together.

As can be seen from that graph, small changes in the electorate voting led to large changes, often super-majorities.

Proportional Representation

Since 1949 the Australian Senate has used the Single Transferable Vote (STV) system of proportional representation . Since 1984 group ticket voting has been an option, this is colloquially known as above the line voting, where an elector can check off a box above the list of candidates and the preferences will be allocated by the parties register order of preferences. This has proved popular , in 2001 ninety-five percent of voters chose this. The Senate has a large number of candidates and rating them all can be a lengthy process.

The benefits of proportional representation in multi-member districts is pluralism, as STV is a better able of reflecting the diversity of political opinion through the election of candidates to a political position. This is obvious in the graph below. The use of STV has seen the rise of third parties in the Senate. By the same token, the STV system has not stopped the major parties from having a majority either when the electorate deems it their choice.

The same graph again, this time accommodating the voting blocks of the major parties. The Liberals/Nationals are red, Labor blue and the third parties and independents yellow;

The Australian Senate is intended as a house of review, one capable of acting as a brake on the Executive. The FPTP system left parties with super-majorities in the Senate. By comparison the use of STV has enabled the representation of minority interests through third parties and independents, it has also not stopped a major party earning a majority when the electorate has deemed it their choice.

The STV voting system is superior to FPTP for the purposes of the Australian Senate, and has yielded superior outcomes since its inception in 1948.

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