He may inhabit the dark side but Andrew Duff is still a penetrating commentator on the ways of the EU, and of British involvement.
Writing for the Policy Network, he has now produced a short paper on "Britain's Special Status in Europe", sub-titled: "A comprehensive assessment of the UK-EU deal and its consequences".
Confirming what we already knew, he tells us that the actual Decision "belongs to the heads of state or government alone and not to the European Council". This point is familiar to readers of this blog, but it remains to be seen how many pundits really understand this.
Furthermore, Duff tells us, under the terms of the Treaty of Lisbon, the European Council cannot legislate for the European Union. Neither can the Council initiate, still less bypass, the EU's official treaty revision process, laid down in Article 48(2).
The procedures for revising the treaties, we are reminded, "involve not only the heads of government but also the European Commission, the European Parliament and national parliaments, meeting together in a convention.
It is true that the heads of government have the last word on EU treaty change, but they do not have the first word. So the Decision takes the form of an intergovernmental agreement lodged at the UN and applicable under international, not EU law.
That Decision, says Duff, will become legally binding under international law if and when the British decide to stay in the European Union. In theory, as the European Council asserted, the Decision will remain legally binding until revoked by a unanimous decision of the 28 governments.
Nevertheless, as the personnel at the summit changes, which they do fairly frequently, the deal will become less authoritative, and may be amended, reversed or ignored.
But then we come to the money quote. "In any case", Duff adds, "the substance of the Decision will not be binding on the EU as such until its provisions have been transposed into EU law".
This must be primary law via treaty change with respect to the sovereignty and economic governance dossiers, and through secondary law via the ordinary legislative procedure in the case of the social welfare and migration issues.
In other words – and there is no other construction that can be put on Duff's interpretation, while the Decision may be binding on the current signatories (but less so on future office holders), for its execution it requires action by EU institutions, and they are not bound by the Decision.
Duff does not say it - although he does make reference to the Vienna Convention on the Law of Treaties – but if a treaty requires for its effect actions by third parties which were not signatories to the treaty, and by virtue of this is incapable of execution, it cannot be a valid treaty and cannot, in any event be biding.
This is the crux of the matter which Duff – Europhile though he might be – is too honest to conceal.
The Decision does not, he writes, bind the European Court of Justice, the European Parliament or the European Central Bank – all of which are set to play important roles in the transposition of the content into the primary and secondary law of the European Union.
The authors of the Decision, he thus concludes, make the bold claim that it constitutes a "new settlement" between the UK and the EU. But, at best, all it could do is "contribute to a successful campaign backing a referendum decision to remain in the EU".
At worst, however, controversy surrounding the Decision will sow confusion in the referendum campaign and further aggravate Britain's relations with the rest of the European Union.
And nor does it end there. Separately, in Euractiv, we hear from Daniel Schade, head of the Project for Democratic Union, and James Bartholomeusz, a policy officer at the same institute.
They say that there is nothing of substance to the UK's renegotiation agreement, but it has been sold as a full revision of the country's EU membership. The concessions David Cameron claims to have won are entirely cosmetic, if that.
The pair concludes that many of those who support the UK's continued membership of the EU, but hold nothing but contempt for his rebranding exercise, must now grit their teeth and pretend that he has done a substantial job.
As for the leavers, I fear we have let go too early. Distracted by talk of Dave's "dodgy dossiers", we have not pursued with the vigour necessary the dishonesty inherent in Mr Cameron's renegotiation settlement, and have allowed him to run with the claim that the UK has achieved "special status".
History is repeating itself – the Wilsonian fudge of 1975 has been transformed into the Cameronian fudge of 2016. Fool me once, they say, shame on you. Fool me twice, shame on me. Are we to be fooled twice, and with something which is so transparently a lie?