Ahead of tomorrow's second reading of the AV referendum bill, Douglas Carswell MP has announced on his blog that he is planning to submit an amendment to offer voters a proportional option. Carswell rightly condemns the restricted choice on the table (without acknowledging that this is down to his own party and its attachment to non-proportional voting): 

The deal on offering us a referendum on AV was cooked up by politicians seeking to cobble together a coalition to gain them power. Hardly new politics. The plebiscite is not being offered to us on the basis of high principle, or as a consequence of careful consideration on what is best to renew our democracy. No wonder the "no" campaign seems to be gaining momentum.

Carswell's amendment envisages a referendum along the lines of the one New Zealand held in 1993, with voters first being asked whether they wish to abandon first past the post, and if so which system they want to replace it:

Following Lucas's announcement last week, this means there will now be amendment efforts to introduce a PR option from both the right and the left.

But not all reformist voices are happy about this. Whilst I welcomed Lucas's efforts on the grounds it would help bring to public attention the fact we are being denied a proper choice and that there are better systems available, Sunder Katwala raised concerns the tactic was an opportunistic attempt to embarrass the Lib Dems and that it paved the way for the Greens to oppose AV. 

I don't think that'll happen with Lucas and the Greens, surely the party will prefer some kind of reform, however limited, to none whatsoever. But in the case of Carswell I'm not so sure, especially given this blog yesterday by his ally Daniel Hannan arguing that "Principled supporters of electoral reform should oppose AV".

At the same time one has to wonder why, if Carswell is such a strong supporter of STV, he voted against an STV amendment tabled by the Lib Dems in February. What has changed since then? Is Carswell playing his part in a broader Tory strategy to divide reformers? This seems unlikely as he is notably independent. But why did he oppose an amendment for STV in February while he backs one now?