WNU Editor: There are two narratives that are underway right now when it comes to who is responsible for this attack.
On one side fingers are pointing at the U.S. .... Whodunnit? - Facts Related to The Sabotage Attack On The Nord Stream Pipelines (Moon of Alabama).
On the other side fingers are pointing at Russia .... Nord Stream pipelines were sabotaged, and the best suspect is the nation that sabotaged them before (Daily Kos).
I personally say it is best to wait before making any judgements. We only know that these pipelines have been attacked/sabotaged. There is still a lot that we do not know.
Update: Most of my friends and contacts in Europe believe the U.S. was responsible for this attack.
Opinion in Ukraine is interesting. While the government narrative is that this was a Russian attack, my Ukrainian friends, family members, and contacts are convinced that this was an attack green-lighted by the US and then handled by them or through a third party.