There's enough smoke and mirrors in the Salisbury poisonings to make the Magic Circle blush. It is impossible for the public to understand what happened, and who did what to whom, not only because the details don't add up, but because many of the so-called "facts" that have been released are suspicious in and of themselves.
Whichever aspect of the case we look at to try to make sense, we can never quite be sure that we are not going down a rabbit trail, since the "facts" we base our case on may in fact not be facts at all.
What we can do, though, is to keep looking at the official claims. The investigators of the case obviously have access to information that ordinary members of the public don't have, and they have made an accusation. But the big question is whether the claims and the accusation they have made stand up to scrutiny - not just to the "facts" that have been given out, but also to logic and to reason.
It is important to begin by defining exactly what the claim is. There are essentially two branches.
The first comes from the British Government, who have declared the Russian State to be responsible for an attempted assassination of Mr Skripal on 4th March (to begin with they hedged their bets between direct responsibility and indirect responsibility, but later statements are more explicit about direct responsibility). In making this claim, because they are not in a court of law, but rather in a Parliament full of remarkably incurious folk, they have been able to able to come up with vague and airy statements about the case, all of which may well be enough to satisfy the incuriosity of that particular audience and their chums in the media, but which are unlikely to satisfy the minds of the more discerning.
Comment: See also: