I can believe that the US was involved.
I strongly doubt that Norway was involved, it would have poisoned relations with the EU.
So... Maybe that's why they won't admit it?
Norway has a system that has been called “fax democracy”, where it has to accept EU laws have supremacy over Norwegian laws, without any veto or democratic representation.
That is not the position of strength from which to launch a sabotage attack on the EU’s largest and most powerful member.
The chances of Canada attacking US infrastructure is zero. The chances of Norway doing the same to Germany is even less.
Not that I know of. I'm basing my speculations on Hersh's article, Biden stating openly that "we'll bring an end to it (the pipeline)" and a bit of "ciu bono?".
I'll stick with Seymour Hersh on this until there's a more credible story, since I doubt I'll live to see the declassified CIA report.
Norway? Why not? They like the Russians as much as their neighbour Finland and they also have gas. According to Hersh's article it offered a base for the operation.