David Cameron's attempts to bus-in support for what most people seem to think is a lack-lustre deal on EU reform could back-fire spectacularly.
In crude terms, what the PM hasn't secured in the reform package will be delivered by means of a bill guaranteeing the superiority of rulings from British courts over those from - well, anywhere else. Well, if not quite anywhere else, then certainly from "Europe".
The detail of what is in this "British Bill" will be even more intensely scrutinised than the final terms of the EU package. Why? Because of the risk of unprecedented levels of emotion and confusion being generated by the debate, destabilising the political landscape with no clear outcome.
Dystopian melodrama? Not a bit of it. Consider the following:
The EU referendum will be intensely debated and divisive on the let as well as the right. The debate will probably be most toxic in Conservative Party. Twenty five years after Major decried the "bastards" in his own ranks, the tensions on this issue are a s taught as ever.
This would be the case even in a stable two party landscape. Factor in a significant anti-establishment vote - UKIP - and the political scales start rocking like a Newton's Cradle.
And the debate will be impassioned. Notions of national sovereignty and identity are powerful at best, but in an uncertain world, with widespread pejorative reporting of mass migration, and in a an economy badly fractured between those who have plenty and those who have barely enough (or less), the prospects of keeping calm and concentrating on the facts and nothing but the facts are ......nil.
So that's just the EU. Now throw in the "British Bill" and see what happens.
First, it will square rather than simply double the volume and everything else associated with the referendum.
I can understand why the PM may take a punt - cock a snook at the ECJ and just hope that our own courts will agree with any ECJ judgments that could potentially cause a conflict. But the ECtHR is a different kettle of fish. Uncouple ourselves from the ECtHR and we opt out of the European Convention of Human Rights too. Do we want to be that delinquent? Do we want to pick a fight on that turf?
Well of course the answer is that some people do. Some do because they confuse the two courts and believe leaving the EU erases the influence of both. (Allowing such misunderstanding to exist, incidentally, does nothing for anybody, so applause to the Mirror for giving clarification.)
Some do because they actively want to remove the Human Rights Act from the statute. This is of course both a Conservative "hotspot" in terms of policy, but also something that they have been unable to vigorously pursue because of the excellent campaign work of Liberty and the objections of MPs such as David Davis and especially Dominic Grieve.
And therein lies a further dilemma - and it may be on this one that the PM gets his fingers badly burned. Either he includes the ECtHR in his list of courts whose rulings are subordinate to British ones or not. It seems he cannot duck this issue now.
If he does, he brings on a political row that he has struggled to avoid throughout his premiership - and with good reason because he fears he will not win. And who knows what trying this and the EU referendum will do to the vote on the latter?
If he does not, he stands open to a furious charge from Eurosceptics that he has sold them short. That the vital totem has been desecrated by its omission.
This could turn into a process with extra-ordinarily high stakes - and that's without all the other hugely controversial pieces of legislation that will creep through under cover of what looks like being a ferocious political firefight.
Irrespective of the vote to stay or leave the EU, the "British Bill" - or more particularly a British Bill of Rights - could well be smuggled through the wake of the referendum. But then again, perhaps that is what the PM most truly desires.
Full disclosure: I am a member of Liberty's Policy Council, writing here in a personal capacity