Just under a year ago, as the big beasts of the Conservative and Liberal Democrat parties hammered out the details of a coalition deal, it seemed like British politics had been turned on its head.

Contra Disraeli, it appeared on those sunny May days that followed, that England might love coalitions after all. The era of the ‘new politics’ had been born. And according to fresh-faced Nick Clegg, this would be defined by “the biggest shake-up of our democracy since 1832, when the Great Reform Act redrew the boundaries of British democracy”.

The centrepiece of that great constitutional transfiguration would be the introduction of the Alternative Vote (AV) for UK elections, an electoral system which aims to elect every MP with over 50% of the vote. Instead of the single cross in a single box next to a single candidate’s name, as under the First Past the Post (FPTP) system, voters would have the option of numerically ranking candidates according to their preference. The least successful candidates are eliminated, and their votes redistributed, until one of the front running candidates polls more than 50%.

As 5 May and our chance to accept or reject AV approaches, and the fog of rhetorical war descends, what might we make of the choice before us? Some religious leaders have tipped their hat this way or that (mostly that, actually), but they have been rightly circumspect about suggesting that there is a theological rationale for supporting one system or another.

Of course, the Christian tradition sees political authority as limited and conditional, and democracy itself is a particularly good way to remind those with political authority that their power is always delegated, always for a purpose, and it can be removed. But that doesn’t help us decide between different systems of doing that delegating and removing. Perhaps, as Tom Wright said in a Theos lecture in 2010, the Christian tradition is more interested in what politicians do when they are in power, than precisely how they got there.

But how about a dose of good old fashioned plain speaking – of letting your yes be yes, and your no be no? Both the yes and no to AV camps have been guilty – and let us assume the best – of making exaggerated claims for their favoured system, or apparently mistaken accusations against the system they oppose. ‘If you want MPs to carry on buying duck houses, clearing their moats out, and obtaining bathplugs on expenses, then don’t vote for AV’, has been one of the more risible arguments. Presumably, IPSA would disagree.

On the other side, the mainstay of the campaign has been the expense of reform; ‘do you want schools, hospitals or the alternative vote’? That – allegedly – is the choice in this referendum. Well, I don’t know about you but I think we should stick with education and healthcare… Layer on top of this the bandying around of imprecise language (‘fairness’, making MPs ‘work harder’, ‘opening the door’ to extremists and so on) and one wonders if the whole debate is not caught in a feedback loop. Exaggerated claims lead to public distrust and confusion, which lead to general ambivalence and disinterest, which lead to more exaggerated claims in a vain effort to create interest, and so on.

No doubt the debate would be well served by paying more attention to those who know enough to clear some of the factual rubble (the London School of Economics have been publishing a series of informed contributions on its politics blog, for instance).

One of the things one might learn is that the two systems are more similar than either camp really cares to admit. Hung parliaments? Slightly more likely under AV, perhaps, but ever more a possibility under First Past the Post. Safe seats? A product of entrenched and predictable voting patterns, not of electoral systems, and a certainty under both options (a paper by the nef suggests 44 more safe seats, though this does not factor in the upcoming reduction in the number of constituencies). Proportionality? Frankly, neither system makes a virtue of that, and AV can be as or more disproportionate than FPTP.  Space to smaller parties? Under both these systems, smaller parties are extremely unlikely to win seats.

However, as we argue in our latest report – Counting on reform: Understanding the AV referendum – we can’t decide between these two systems simply by objectively adjudicating between comparative examples, statistics or electoral predictions. Rather, we have to ask ourselves, how do we expect democracy to do its core work of both legitimating and holding political authority to account? When cast in this light, we see that the referendum debate has become a cipher for the ongoing contest between two different visions of democracy.

Do we elect people in order to create a socially reflective public assembly, an institution where all interests and groups are represented? Or are we looking to pick the right team – the senior ministers of government – who are then free to make decisions in what they think is the public interest. Alternatively, do we think that good government emerges from a constantly negotiated consensus of interests, or from giving a government a mandate to lead according to a defined mission and purpose, over which the public can stand in judgement at the next election, and – if they so choose – judge harshly and eject the government in question?

Our answers to these questions rest on assumptions – albeit not unreasoned ones – about what a good democracy looks like. So when you come to cast your vote, the real question is not ‘to AV or not to AV?’. Rather, it is ‘which vision of democracy is the more realistic, the more convincing and the more satisfying?’

Paul Bickley is Senior Researcher at Theos.