Anyone who says they know "who and why" is blowing smoke up your fundamental orifice.
I've heard a number of opinions today and the only one that holds water IMO is Russia dunit.
This is not a declared war, merely an "intervention" which leaves Gasprom open to multi-billion damages for breach of contract if they fail to deliver gas. Europe is now "making other arrangements" so the pipelines may never carry gas on Russia's terms again, so they blow the pipes, call force majeure on the contract and save billions. Of course it doesn't harm their war effort, short term.
But I put this forward merely as ONE [sorta] logical explanation. I'm not blowing smoke up ya bum and I see benefit for USA if they wish to play dirty.
