> Russia because they could put pressure on Europe.
That doesn't really hold because they could just turn off the tap
On the other hand blowing up the pipe means giving up on :
1. blackmailing the europeans if they don't comply to some demands. 2. A huge revenue - because BTW there's no way it can be repaired.
So I don't think contractual ramifications weighs much in that context
But from historical perspective, the one thing that outlives wars, is Debt and Contracts. Specially if they are owned by the winner.
In any case, Russia could 'turn the gas off' by having 'irrepairable turbine failures' or various other technicalities.