The status quo isn't what it used to be.

 The status quo isn't what it used to be. In the old days, you knew where you stood when you voted No to constitutional change. You would be voting for things as they are - whatever arrangement happens to apply at the time of voting. Not any more. This weekend it is impossible to say what the current state of play is on the constitution because all the unionist parties are proposing radical changes to it.

The status quo is now a process not an event, to paraphrase Donald Dewar. There was David Cameron last month, after his meeting with Alex Salmond, announcing that there could be “more powers” for the Scottish parliament. A week later, Alistair Darling – no enthusiast for fiscal autonomy - caught the bug and announced that to be responsible a parliament “should raise the money it spends”. Last week, leading figures in all three unionist parties got together to promote “devoluton plus” under which Scotland would acquire powers to raise income tax, corporation tax and oil revenue, while leaving VAT and National Insurance with Westminster.

Now, this weekend, the new leader of the Scottish Labour Party, Johann Lamont, has announced that she will lead a new commission on devolution, a kind of Calman plus, to look at new fiscal powers. This parallels the commission already set up by the Scottish Liberal Democrats under their former leader, Sir Menzies Campbell, to look at a federal option. And there is the Future of Scotland initiative – an umbrella of various “civic Scotland” groupings like churches, charities and trades unions, who met last week looking at form devolution max .

Suddenly you can't move for commissions on fiscal devolution. It makes the unionist demands for an early referendum on independence look oddly premature. If there were an early ballot, what on earth would Scots be voting for? Independence is clear – sort of. Alex Salmond at least seems to know what he is talking about. But on the other side there is now a shifting kaleidoscope of constitutional formulas occupying the unionist space.

The unionists' priority of course is come up with a something, anything, to block the march of the SNP, following its election landslide victory in  May. Figures like Douglas Alexander, the Shadow Foreign Secretary, have been urging the Scottish Labour party up to understand the extent and significance of its defeat and start thinking constructively about more powers for Holyrood. But Lamont, who says she will be leading the No campaign with Alistair Darling and Gordon Brown in support, is still grudging about what she calls the “virility” test of more powers. She is even hinting about powers being taken away from the Scottish parliament – not so much devolution plus as devolution minus. Right now, bizarrely, the UK Labour party seems more radical on the constitution than its Scottish counterpart.

So, where does all this leave the state of the union? Do we have any clear idea where the status quo is going? Well, they haven't said it explicitly, but the parties are clearly heading very rapidly towards a consensus on devolution plus, if only because there really is nowhere else to go. The Scottish parliament, to satisfy voter opinion, simply has to have a new funding arrangement more radical than that offered in the current Scotland Bill. The idea of splitting income tax between Holyrood and Westminster, proposed by Calman in 2009, was always a difficult sell and it is now well past it. Devolution max is a bit too like independence, since it involves Scotland raising all taxes and sending a contribution south for common services like defence.

Devolution plus is the only credible unionist destination short of independence. It is the unionist Maginot Line – the line beyond which Alex Salmond shall not past. It is also almost certainly what the Scottish voters would vote for – if the unionist parties would only let them. Perversely, all three unionist leaders are still insisting that there should be no opportunity for Scots to have a say. But how else are the voters to have any confidence that this better devolution will actually happen? Unionists can't simply offer promises of what might be if the Scots are good boys and girls and reject nasty Mr Salmond. Everyone knows that if the referendum returns a No to independence in 2014, then the unionist parties' enthusiasm for more devolution would rapidly evaporate. If they refuse a second question or a second ballot, then the only alternative would be to move a new Scotland bill, replacing the one limping through the House of Lords. But come the referendum, if all the unionists offer is jam tomorrow, I wouldn't put it past the Scottish voters to back independence in order to be sure that they get a better devolution.