[hackerlight]

Really, either speculation is equally valid (or should I say, invalid) without:

(1) An understanding of the facts of how successful the EU has been at diversifying away from Russian gas and whether NS2's natural demise was all but an inevitability.

(2) How much the repairs will cost.

If the repair costs are low, it's probably Russia, because of the propaganda value.

If NS2's demise was highly likely, again probably Russia because they're leveraging a sunk cost to their benefit which is just smart.

But so many people are making confident assumptions about (1) and (2) in this thread. If you don't know the answer to those questions, stop forming strong opinions!