A bigger Lib Dem consolation prize if AV is lost
If the Alternative Vote (AV) referendum is lost then the Liberal Democrats have a fall back reform which could deliver them a far greater prize in the long term than the Alternative Vote. And that's reform of the House of Lords.
Most psephologists reckon that AV would have given the Lib Dems perhaps 15 or 20 extra seats at the 2010 election. And the Lib Dem gain from AV would be a lot lower if their support falls to the kind of levels currently suggested in the polls.
AV would be nothing like as rewarding as proper PR, under which the Liberal Democrats would have got around 140 seats in 2010. And contrary to what the No campaign have been suggesting, AV wouldn't give the Lib Dems a permanent place in government or mean that we will have coalition government for evermore. It only makes such outcomes a bit more likely.
In contrast, Lords reform could give the Lib Dems a lot more power in the long term - what might almost amount to a permanent veto on legislation.
The Coalition Agreement commits the parties to a new upper chamber that would be "wholly or mainly elected". That's now likely to mean 80% elected, but also, crucially, it is generally expected the new chamber would be elected under proportional representation (PR).
That would probably mean the Lib Dems held the balance of power in the new upper house on an almost permanent basis. So even if future governments had a majority in the Commons (thanks to First-Past-the-Post), they could only get legislation through the Lords with the approval of the Lib Dems.
OK, you can argue that neither this government, nor its Labour predecessor had a majority in the Lords, so they, too, have had to build consensuses among peers to get their bills through, and under Labour that usually meant Lib Dem support. But the Liberal Democrats' position would be far more powerful in a democratically reformed PR Lords.
First, in the current Lords the 93 Lib Dem peers have to compete for this balance-of-power role with a much larger group of 184 independent cross-bench peers. It depends on the detail of the reformed Lords, and presumably there will be some role for independents, but nonetheless the crossbenchers are likely to be a much smaller group in a chamber that is primarily elected.
Second, the elected nature of the second chamber will give it a greater legitimacy than now, and so it will be less likely to back down in disputes with the Commons (a reason many MPs are wary of making the Lords more democratic).
A draft bill on Lords reform is promised before the end of May. However, many in politics are sceptical that the Lords will ever be reformed during this Parliament, not least because any such plans will meet stiff opposition from the current upper house. But if the Lib Dems lose the AV referendum then they are likely to press more strongly for Lords reform. And David Cameron is more likely to agree, so as to keep the Coalition going.
But many Conservatives will be applying counter pressure. Many Tories are upset with Mr Cameron for twice making what they see as huge electoral concessions to the Lib Dems - in granting equal billing to Nick Clegg in the TV debates, and then the AV referendum.
If the Lib Dems achieve the prize of a PR Lords, and hence a permanent boost to their strength at Westminster, then all of the current grief of belonging to the Coalition could prove worthwhile.