We're probably all good barrack-room lawyers around here (though no actual lawyers have ever made themselves known as such in BTL comments). So there can easily be fine points of law we're missing.
But - WTF are the Supreme Court exercising themselves over?
Seems to unqualified me that they are being asked to opine on whether the government's perfectly legal action in advising HMQ to prorogue Parliament, was taken for ulterior motives, i.e. other than that stated (= need to limber up for a Queen's Speech for the forthcoming legislative session).
So - is the argument that a politican not acting in (someone's assessment of) Good Faith is thereby unable to act in ways that are legal?
As regards the assessment bit, it's fair to say that judges and juries frequently take a view on motivation: some charges that are laid before a court positively require that they do. So it's OK (I think) for them to consider what Boris' motivation was.
But: are we to allow that "politicians speaking with forked tongues" is a disqualifying factor on the actions they take? And if so, just how often are the courts going to be invited to intervene?
Take a simple example. We all know that when Corbyn ostensibly refuses to believe evidence that it was the Russians who let fly with Novichok in Salisbury, it's because he's a lying leftist shit who takes money from RT. Suppose he was in power, and took this attitude to be a reason to intervene and prevent the security forces from pursuing their inquiries? Does Gina Miller rush to court to obtain a ruling that his action wasn't in good faith?
For that matter, what about 90% of the oeuvre of Tony Blair?
Seems to me we have always known politicians speak with forked tongue, and that it's their actions per se that should be the focus of practical attention, not the "window on men's souls" the court is being invited to attempt to open up. We have other ways to reckon up with them if we conclude they are inveterate liars.
And who knows, in due course maybe that's what the court will find.
Meantime: what do other amateur lawyers think?