I respectfully submit, I have to show that the nature of the parliamentary intervention that there has been in this context, from 1972 onwards, allows the Government to continue to exercise its prerogative powers on the international plane, and I have to show that the nature of that parliamentary involvement can and does, as it were, with Parliament's permission, create effects into domestic law.
I say that is not a question of analysing it as though there were some freestanding constitutional principle which provided the answer. I say that the correct approach to answering that question is not to ignore the entire legislative scheme and come at it on the basis that there is an a priori constitutional principle in play.
The reason that the constitutional principle is advanced in the way it is by my learned friend Lord Pannick and others is because, when they get to the statutory scheme, the argument becomes extremely difficult for them. For reasons I will develop, they have a great deal of difficulty explaining away what on earth Parliament thought it was doing if they are right in the 2008, the 2011 and now the 2015 Act.
So what they do is to say: you don't need to go anywhere near that, you don't go near De Keyser, you don't go near the legislative scheme that Parliament has seen fit to enact; and the solution to this case involves standing back, sweeping all that away and just saying: there is the constitutional principle.
So we fundamentally do not accept that way of approaching the case. We say that the right way of approaching it is to look at the legislative scheme in its entirety and to ask what that scheme tells you about Parliament's intention on the base question that I identified at the outset.