AV SCENARIOS

We don’t know what the alternative vote would mean if Britain votes yes in the referendum, but there are several educated guesses on offer, and until we have an AV general election they’re all about the Liberal Democrats. What would happen under AV? Here are the best attempts at scenarios ...

1. The Liberal Democrats do rather better or hold up; otherwise business as usual

Why it might happen
Preferential voting means than voters’ second choices are crucially important in some seats – and because the Lib Dems would probably have been most Labour and Tory voters’ second choice last general election around, most of the pundits reckon that the Lib Dems would have won 20 or so more seats if the 2010 general election had taken place under AV. In other words, AV would benefit the Lib Dems.

Why it might not
However the Lib Dems did or might have done in 2010, we’re never going to re-run anything like the 2010 general election – not least because the Lib Dems entered coalition with the Tories in 2010. It is still plausible that under AV, in most constituencies, most voters for the two big parties would chose the dull centrist – the Lib Dem – as their second preference, but nobody really has a clue. “Imagine if …” opinion polls are dodgy.

Prognosis
The Lib Dems might have done better under AV in 2010, but they are a lot less popular right now. OK, there isn’t a general election any time soon as far as we know, let alone one under AV – though we could all be surprised – but many Labour voters are so antagonistic towards the Lib Dems that they wouldn’t even consider transferring even in a Lib Dem-Tory marginal: result, more Tory MPs. In Labour-Lib Dem marginals, the Lib Dems need second-preference Tories. Would they get them? Doubtful right now.

2. The Liberal Democrats do very badly; otherwise business as usual

Why it might happen
The Lib Dems are very, very unpopular, and they could just go into meltdown. In general elections under AV, if their first-preference support went through the floor and hardly anyone put them as second choice, they could find themselves eliminated or nearly eliminated from the House of Commons – back to their 1959 representation, a couple of patrician eccentrics from the far corners of Scotland – because in nearly every one of their currently held constituencies they would be beaten on second preferences (mostly by Tories but sometimes by Labour).

Why it might not
The Lib Dems could keep up their support regionally and in Scotland and Wales if they play their cards right. The English local elections and the Scottish parliament and Welsh assembly votes next month are very important here. Scotland and Wales complicate any scenario big-time: the Lib Dems have openings to Labour if they do well enough in Scotland and Wales next month, which might just be enough to allow them to distance themselves from the Tories, at least among the Scots and Welsh, at best by joining Labour in national administrations. The problem, of course, is that all the crucial elections happen on the same day as the AV referendum.

Prognosis
The Lib Dems have wriggle room in an AV system if they do well enough to become coalition partners with Labour in Scotland and survive in Wales as a significant force next month. But if they do really badly in the Scottish Parliament and Welsh Assembly elections they are well and truly marooned even if Britain votes for AV. And that leads to …

3. The Lib Dems enter a semi-permanent coalition with the Tories

Why it might happen
If the Lib Dems are stuffed in Scotland and Wales and if their opinion poll ratings are in the doldrums coming up to the next general election, if the coalition is still alive, and if the Tories are also struggling ... OK, a lot of ifs, but entirely plausible … it would make sense under an AV system for the Tories and Lib Dems to sort out a formal preference pact in which both governing parties advocate second preference voting for the other to maintain the coalition government. After that, it would be difficult (if they won) not to keep together in government.

The Lib Dems would have to be in dire straits to accept it, but that certainly can’t be ruled out; and the ideological small-state free-market empathy is there between Clegg and Cameron. Such a deal also goes with AV historically. In Australia, voting is all about the two centre-right parties – which are in permanent coalition – Hoovering up each other’s second preferences on the basis of pre-electoral preference pacts, with Labour (after a long time in the political wilderness) playing the same game informally with greens, the far-left and dodgy populists.

Why it might not
Well, Scotland and Wales. If the Lib Dems do OK there, they wouldn’t need a pre-election preferences deal to survive at Westminster under AV – they’d be able to pick and choose – at least at the next election. But after that?

Prognosis
There’s a good case for thinking that a permanent coalition of the Lib Dems and Tories is a very plausible long-term scenario under AV – if a lot happens that might not. For Labour, there's a real danger of another 1931: complete marginalisation for a generation through the unification of its mainstream opponents into an anti-Labour bloc (and Labour is just as vulnerable as in 1931 to just such a marginalisation).

4. The Lib Dems enter a semi-permanent coalition with Labour

Why it might happen
If by some miracle the Lib Dems survive the coalition without formal Tory endorsement on second preferences under AV, and they’re in power with Labour in Holyrood, who knows?

Why it might not
This scenario seems rather implausible as long as the Lib Dems are in coalition nationally with the Tories and cutting spending with Friedmanite enthusiasm.

Prognosis
Not impossible but unlikely. Labour has every reason to exploit every internal difference within the Liberal Democrats for the foreseeable future, but no reason to expect a lot from it.

All right, this is guess-work. But that's what we'll be voting on in a fortnight.