No one supports the unionist status quo anymore.

For once the hype was justified. “The most important debate the Scottish parliament has ever engaged in” said the Scottish Tory leader Annabel Goldie during last week’s debate on setting up a Constitutional Commission to extend home rule. She could be right. All the major forces in Scottish politics are now united as never before on the need to give Holyrood more oomph - to turn it into a proper parliament with full domestic powers and its own tax base. Even the SNP is part of the consensus, though Labour is trying to lock them out.

For hacks like me who have watched the battle for Scotland for over twenty years, this is hard to believe. Ultra-unionists like the Scottish Tories joining forces on the constitution with the ultra-devolutionist Liberal Democrats? Surely not. Michael Forsyth would be turning in his grave, were he dead. Annabel Goldie as a tartan revolutionary, a blue rinse madam Ecosse? Well, she delivered a powerful speech in last week’s debate, admitting past mistakes and conceding that home rule is a process that “dwarfs party politics”.

But Labour’s conversion is equally remarkable. Eight months ago it fought the Holyrood election with Gordon Brown ruling out any further powers for the parliament, let alone giving it a new tax base. Perhaps if Labour had proposed a cross party constitutional commission - as this column urged - before rather than after May 3rd, it might still be in power. It confirms everything we suspected about the Labour campaign - that it was driven by London Labour priorities rather than Scottish ones. Labour activists could be forgiven for asking why they had to lose the election to return to the mainstream.

But credit where it is due: Wendy Alexander boldly faced down her own boss, the Scottish Secretary, Des Browne, in her speech last week by declaring that devolution is indeed “a process not an event”. Browne had insisted in August that it was the other way round, and he even denied that Donald Dewar had ever used the phrase. She has also directly contradicted Gordon Brown’s pre-election veto on new powers.

This change has of course been inspired by Alex Salmond’s own “national conversation”, launched in August, which unlike the proposed Constitutional Commission is genuinely non-party, consensual initiative. At its launch, Salmond welcomed the participation of all strands of Scottish opinion, and pledged to work with any party which sought to extend Holyrood’s powers. “A government should never be afraid”, said Salmond, “to test its own preferred policy against the alternatives”. Unfortunately, this is a test the opposition parties have flunked.

Labour has drafted the terms of the proposed Constitutional Commission specifically to exclude any consideration of independence. This really doesn’t make any sense and undermines the credibility of the entire exercise. It really isn’t possible to discuss constitutional future of Scotland without considering one of the leading constitutional options. Their commission is to be funded by the Scottish Parliament yet it has barred the party of government. What are they afraid of? Surely the SNP has more to fear since only around 25% of Scots favour separation.

Wendy Alexander invoked the spirit of the original 1988 Scottish Constitutional Convention last week, but she really isn’t entitled to claim legitimate descent. That convention was a genuinely non-party body which invited the nationalists to the table; Wendy’s convention is a political device for marginalising the SNP. This is the reverse of what happened in 1988 when the SNP, under deputy leader Jim Sillars, boycotted the original Scottish Constitutional Convention, and opted for political irrelevance for the next decade.

Nor is it possible to take seriously an exercise that seeks radical constitutional change without consultation. The Liberal Democrats rightly see the starting point of the Constitutional Commission as being their own report on the constitution conducted by Lord Steel two years ago. It called for Scotland to gain powers not just over broadcasting, drugs and firearms, but also over things like welfare and immigration. In his speech on Thursday, the LibDem leader, Nicol Stephen, called for Holyrood to be given the power to raise personal and business taxes. It is inconceivable that the creation of a federal state - for that is what this amounts to - could happen without some test of Scottish opinion - without seeking the consent of the people of Scotland in a referendum. I can see no way that Westminster would allow it otherwise, and MPs are to have a say on the proposed Constitutional Commission.

Indeed, the participation of Westminster Labour MPs does also rather raise questions about the opposition parties’ sincerity. Many Scottish Labour MPs loathe Holyrood, don’t accept Wendy as their leader, and are hardly likely to endorse the kind of “devolution max” proposed by the Liberal Democrats. It is only a matter of weeks since the Scottish Secretary, Des Browne, was talking about taking powers away from Holyrood. Is he going to be part of the process he denies the existence of? The suspicion is that Labour’s real ambition is to indulge in a metaphysical debate about constitutional options which eventually endorses the status quo.

But that is no longer an option. The idea of a parliament living on a handout is now totally discredited. Labour’s own performance in office has been ample confirmation of that. The argument for tax-raising powers is now unanswerable, as Wendy Alexander has conceded. So is the case for powers like broadcasting to be repatriated to Holyrood. Merely by aligning the opposition parties behind these propositions, Labour has made them inevitable.

They may think they have outmanoeuvred the nationalists, but in reality they are playing into Salmond’s hands. He will simply welcome anything the commission comes up with. Indeed, SNP ministers haven’t ruled out participating in the convention in some way or other, for it presents no downside for them. They will embrace its findings as a constructive step on the road to self-government, furthering the case for a referendum.

As Annabel Goldie rightly observed, there are forces at work here which are above party politics and which Labour only dimly comprehends. Scotland has changed. The opposition parties have started something here which they cannot control, any more than the SN can. The collapse of the old unionist consensus will drive Scotland down the road of autonomy.

The only obstacle to this process is, paradoxically, the political parties themselves. We now have two parallel constitutional initiatives underway now - the SNP’s conversation and Labour’s convention - which may be going in the same direction, but which will spend much of the journey bickering and fighting with each other. This tribalism cannot ultimately stop the home rule process, but it could significantly delay it.

It is time, perhaps, for civil Scotland to come to the aid of the parties. To help them work together, at least to the extent that they agree change is necessary. The Sunday Herald will be hosting its own non-party conversation this week with civic bodies representing the major strands of constitutional opinion in Scotland. No options will be barred from this forum, and the only people not invited are politicians. Hopefully, through initiatives like this, a way may be found to save the political parties from themselves, and ensure that the process doesn’t become a non-event.