One of the most important features of the process of devolution is how it draws supposedly unionist parties into trying to one-up the actual separatists in their belligerent attitude towards British institutions.

Most recently, this ‘more powers!’ reflex has manifested itself in two important ways. It has induced the Scottish Conservatives to indulge the SNP’s nonsense about a ‘Westminster power-grab’ against the devolution settlement; and it has just led Labour and Liberal Democrat MSPs to row in behind Nicola Sturgeon’s ‘veto’ of the Withdrawal Bill.

That the First Minister has managed to hold onto them is, in some ways, quite remarkable. The idea that the Government was secretly plotting against devolution was useful nonsense which allowed Edinburgh and Cardiff to squeeze a great many very damaging concessions out of Westminster.

But having won those concessions, the Welsh Assembly has given consent to the Bill. Wales, which has a Labour/Liberal Democrat government. Yet their party comrades in Scotland have decided instead to support the SNP’s version of events – events engineered by the Nationalists with the sole intention of trying to rouse the ire of the Scottish public against the British state.

Sturgeon gambled heavily on the popular idea that Scottish voters would not abide being ‘dragged out of the EU’ in the immediate aftermath of the referendum, and their stubborn quiescence has cost her dearly. It makes sense for the SNP to try and pain this conflict in the most dramatic possible terms. It is more difficult to see how supposedly unionists parties can justify supporting her, now that the Welsh have scotched “threat to devolution” fiction.

Despite some excitable headlines, this is not a ‘constitutional crisis’. The British constitution is actually pretty well-engineered to avoid those, despite Tony Blair’s various initiatives. The sovereignty of Parliament is an elegant mechanism which allows for the resolution of any dispute, and the unblocking of any jam in the system, if the will is there.

Theresa May is right to “push on” with the Withdrawal Bill. As she said in a speech shortly after becoming leader, it is important for the Government to defend the role and prerogatives of UK institutions. To bow before the SNP’s conjured veto would be to send yet another signal that government by our united Parliament were somehow illegitimate.

But the Government should tread carefully nonetheless. With Labour and the Liberal Democrats providing them with the appearance of a ‘popular front’, the Nationalists may be better able to stir up anti-Westminster feeling than they could when pitching for independence, which remains unpopular.

Finally, these events should prompt some re-thinking amongst the Scottish Tories. For whilst Ruth Davidson’s troops have rightly chosen to fight the Scottish Government over the Withdrawal Bill, they were playing the same game as their Labour and Lib Dem counterparts when they colluded with, and thus bolstered the credibility of, the SNP’s line about a ‘threat to devolution’.