“How America took out the Nord Stream pipeline”

Seymour doesn’t provide any proof or any evidence. It’s argument by assertion. What he writes is plausible but without any sources or other corroborating evidence. I think it more believable that Seymour has been paid to write this by a Russian aligned entity.

I don’t know the truth of the matter and Seymour could be right. We just can’t tell from the evidence provided.

If you look at all the players, their interests, and their capabilities, I think the most logical conclusion is that the US likely did it. Of course this is not evidence but this the sort of operation where success means no evidence (at least no evidence available to the public at large as it is possible and, one might hope, likely that neighbouring countries know).