Biden himself told they would do it, and "promised they have ways to do it" (from ca 1:20):
It does make it hard for Germany and Russia to have energy trade, however.
Which makes it easier for the USA to sell its dirty gas in Europe.
I'm reminded of the worm that was injected into NASA servers back in the '80s that eventually made its way into DOE servers (creating a possible nuclear crisis because the DOE deals with two things: energy policy and the posture of the American nuclear response system). Direct initial investigation pointed to the worm originating from servers in France, but further investigation revealed that those servers had been compromised, and the likely origin of the worm was hackers in the Australia / New Zealand area. The likeliest catalyst for the attack: France's blatant destruction of the Rainbow Warrior in a New Zealand harbor. The attack ended up serving two purposes: bloody the nose of the Americans, who were (in the eyes of the attackers) playing fast-and-loose with nuclear payloads on NASA missions; and if their antics were discovered, embarrass the French with how easily their servers had been compromised. Essentially, a double-"don't fuck with us" via cyberspace from the Aussies or New Zealand.
I'm saying that the thing about being an armchair politico on a forum and not a member of an Alphabet Soup organization is that unless someone claims responsibility we won't know who actually did it until maybe a half-decade to a decade out when all investigations are concluded and the various international intelligence agencies and private journalists get the story straight.
They were very certain France hacked NASA until they weren't.
(Something like Biden's loose lips is only further cover for another cloak-and-dagger actor, state or private. Until and unless some country or group comes right out and claims responsibility, all manner of idea-tossing on this forum doesn't give us more than a well-shaped question mark on who actually did it).
Policy hasn't worked, in years. In spite of the US' worst efforts, Nord Stream was built and completed and could actually be used to peacefully engage in energy economy between Russia and Europe.
This alliance is intolerable to the USA, so: the last act was destruction.
Lets see, anyway. Evidence is going to be important on this case.
"Fun" fact, mostly unrelated: the Baltic sea floor is full of unexploded munitions from WW2, and some (still?) contained chemical weapons.