Briefly. I'll be voting no on AV. Here's why:
AV is not PR.
PR is not good.
AV is not good.
Nick Clegg is not good.
Here's why PR is not good:
Britain, like most developed democracies, is basically a kind of elected dictatorship. The state is controlled by a self-selecting group of elites. Factions within these elites vie for direct control over the state. One of the cool things about the constitutional arrangement and/or culture of Britain (as opposed to most polities in history)(and in common with other successful democratic polities) is that there are lots of feedback mechanisms in place to prevent extremes of bad behaviour on the part of whichever faction of elites is in power at any given time.
Examples of these include free press, rule of law, independent judiciary. Stuff like that.
One of these feedback mechanisms is the election. Elections are held every so often and basically acts as a pointy stick with which to prod the various elite factions into behaving in a fashion that people are willing to put up with (where here "put up with" means that the vast bulk of the population are not driven to engage in the violent overthrow of the state, like these guys). The sanction is fairly straightfoward: the faction in power loses power if the voters are pissed off with them.
Obviously "democracy" in this conception has very little to do with the idea that the desires of "the people" have some influence on policy. Maybe they do. But there's always going to be at least 20% of people who are pissed off about *any* given policy. You can't please everyone. Really.
OK. So what does all this have to do with PR and FPTP?
Well FPTP is superior to PR because of the following:
i) It makes it easier to throw a government out of office. It means particular parties know their power is based on the general consent of the public and not on what they can wrangle with the other parties after the election. It means when a specific group of elites with a specific ideological platform start pissing people off then they and their specific ideological platform get booted out of office and get to cool their heels for a bit.
ii) It means there is a clearly defined "opposition" to hold the current government to account. Under PR there will presumably be a greater number of parties. It also means that any governments that do emerge will probably be coalitions. This multitude of factions combined with the possibility that any particular party not-currently-in-government might be able to get in government in order to prop up the governing coalition, means that there is insufficient oversight of government.
iii) It avoids the problem of parties with small portions of the vote remaining in government over long periods due to their always being required to make up a coalition. This means that whoever makes up this faction of floaters will not be subject to the same electoral discipline as parties under FPTP and they can basically do what the fuck they like regardless of the consequences.
iv) It leaves clear ideological space between parties. Parties will not succumb to the "chilling" effect of knowing they may one day have to form a coalition with one or more of their opponent parties. People also have a reasonable expectation that under FPTP they will be able to give "the other lot" a chance to rule for a bit.
v) Good old-fashioned Lor' o' the Shires, si non confectus non reficiat, big B, small c, Burkean conservatism. About time someone actually gave this a try if you ask me.
Now FPTP isn't perfect in this regard, or even at all. But it isn't obvious to me how PR or AV is better.
Now so far I've been arguing specifically against proportional representation (STV is the one I had in mind, YMMV), which AV ain't.
So if AV isn't FPTP, and it isn't PR (which sucks anyway) then why the hell are we being offered it?
The answer is that Nick Clegg needs to deliver some kind of electoral reform in order to maintain credibility (or whatever) as leader of the Lib Dems. And this brings us to the single biggest reason why it's worthwhile to vote no on AV:
*It might destabilise the Coalition*
If Clegg can't deliver the big constitutional whatsit all the Lib Dems want then the Lib Dem cost-benefit analysis of remaining in the Coalition starts a-tilting towards a cut and run.
Now I'm not sure this'll happen. Too many Libs have been bought off with gimcrack Ministerships and the prospect of red leather. But it's worth a shot, and it's not like AV is worth that much anyway.
Anything that helps destabilise and potentially break the Coalition is good because they are currently pursuing a failing and harmful economic policy, and using the ongoing economic crisis to further a pernicious small-state neoliberal agenda that seeks to further undermine our remaining social democratic institutions and further the interests of a handful of wealthy bastards at the direct expense of poor people. Basically.
Now so far I've been going on about PR and why we need to give Clegg a slap. Here's why AV is no good even when considered on its own terms:
1) It isn't proportional (not that this matters, see above).
2) It basically strengthens the third party at the expense of everyone else. Many of the objections to PR expressed above apply to this, but also: the lib dems suck.
3) The bit about "majority support" within constituencies is a reasonable point. But this doesn't cut much mustard when viewed against from the perspective of the vague description of how democracy actually works I gave above.
And frankly I owe Clegg a poke in the eye for enabling this shower of idiot Tories.
I am not against constitutional tinkering per se. Even if I am broadly sceptical of PR. My hypertrophied sense of order would like to see the King in Parliament turned into an actual directly elected president and full separation of powers. And parliament somewhat beefed up in terms of its relative political power to the executive. Of course I'm sure this is a ridiculous idea that no one in their right minds would actually implement. Heigh ho.