The Coalition’s decision to hold the referendum on AV so early is fraught with risk. If AV is defeated at the ballot box, then Nick Clegg will face huge pressure from elements of his party to quit the Coalition. The argument would go that all the Lib Dems were getting out of staying was providing cover to the Tories on cuts. But if AV passes, then there’ll be some Lib Dems who’ll say that they’ve got the best thing they can out of the Coalition and so they might as well head back into opposition to try and restore the distinctiveness of their brand.
On the No side, I expect there’ll be a ferocious campaign against AV. There are two putative No campaigns at the moment and both are quite prepared to make arguments that might make life uncomfortable for the Coalition.