In last week’s Current Debate, Jonathan Chaplin (whose writing I like, respect and usually agree with) argued that the defining purpose of elections is to represent the people’s views. ‘The primary concern,’ he argued, ‘is not with the output of elections but their input – how they express the range, diversity and complexity of the people’s views.’ ‘Elections aren’t a mere instrument of effective government,’ he explained, ‘They are the most important constitutional process by which governments become “representative”, and so – in a democracy – legitimate.’ On that basis, he claimed Proportional Representation (PR) is a moral and political imperative.

In arguing as he does, Chaplin is half right, but fundamentally wrong. How so? Well, the place to start is by understanding the role of a Member of Parliament. In a sense, politicians are elected to a priestly role, representing their constituents to parliament and parliament to their constituents. The defining purpose of elections is not to choose delegates. MPs are elected to parliament to make decisions on behalf of their constituents, not simply represent their majority view. MPs are free to vote and act on the basis of their own conscience, without recourse to the electorate every time the division bell rings.

The practical effects of representative democracy are clear. Consider capital punishment, for example. In the UK, 54 per cent of people support the death penalty while 30 per cent are against it. However, MPs have rightly and reasonably, after in-depth debate and reflection, consistently opposed the re-introduction of capital punishment.

Now that the role of an MP is clear, the reasons against PR can be considered. There are three: PR gives smaller parties disproportionate power, breaks the clear link between an MP and their constituency, and, thirdly, makes it more difficult for voters to remove a party from power.

Contrary to popular opinion, Proportional Representation is unjust. It gives smaller parties disproportionate power. I support the current coalition between the Conservatives and the Liberal Democrats, but let’s reflect briefly on the process which has got us here. In the 2010 general election, 36.1% of the electorate wanted a Conservative government. 29% voted Labour. Only 23% wanted a Liberal Democrat government. The result of the election was a ‘hung’ parliament with no party gaining an overall majority.

Consequently, the Conservatives and Lib Dems were required to agree a deal between themselves in order to form a government that could command majority support in the House of Commons. So, a party with only 23% of public support is now in government. Under First Past the Post, hung parliaments are the exception (the last one was in 1974). Under PR, they are the norm. And hung parliaments put power in the hands of politicians not voters. In 1997, under PR, the Liberal Democrats would have been in government with only 16% of the popular vote.

The Single Transferrable Vote (STV) system is the Liberal Democrats’ preferred model of PR. This is a preferential system in which votes are initially allocated to a voter’s preferred candidate and then, after candidates have been either elected or eliminated, any surplus or unused votes are transferred according to the voters’ stated preferences. STV uses multi-seat constituencies thereby breaking the clear one member, one constituency link. This undermines local democracy. First Past the Post gives one constituency one representative, ensuring that the MP remains accountable and responsible to his or her constituents. In the recent scandal involving parliamentary expenses, people knew who their local MP was and were able to hold him/her to account. In breaking the link, PR makes MPs less directly accountable.

The third problem with PR is that it makes it more difficult for the electorate to kick a party out of power. In 1997, voters sent a very clear message to the Conservative government that its time was up after eighteen years in power. The First Past the Post system delivered a decisive result. The Labour party secured 43.2% of the popular vote, the Conservatives 30.7% and the Liberal Democrats 16.8%. Labour won a landslide victory with their largest parliamentary majority (179) to date. Professor Anthony King has described that election as being like ‘an asteroid hitting the planet and destroying practically all life on Earth’. Under PR, the Conservatives could have, theoretically, been back in power in a Lib Dem coalition, something that would not have reflected the electorate’s wishes.

It’s crucial that the basis for any voting system is the common good. Contrary to Chaplin’s view, elections are about output not only input. Certainly, there are plenty of other non-democratic systems of government (some are quite good), but, as Churchill quipped ‘Democracy is the worst form of government except for all the others.’

So, on the basis of the arguments set out above, we should avoid PR like the plague. Instead, we should continue supporting a system which, although imperfect like democracy itself, has a proven track record of doing what elections should do, namely putting governments in and out of power.

James Collins is a human rights lawyer.