Based on the information that has been presented to the public the case looks quite weak. For reasons I think should be obvious, I'm not willing to simply take the CIA's conclusions on the assumption that they have some secret evidence I haven't seen.
The other "theory" is the idea that the Clintons had Seth Rich killed or that it was another "insider" "mad about Bernie" even though he lost by several million votes.
I don't find the insider risk idea hard to believe. The primary stuff is still an open wound, and you could also easily imagine someone disgruntled for more prosaic reasons (e.g., passed over for a promotion). The fact is we have very little evidence for any of these ideas, and I, for one, don't find it reasonable to conclude that it is therefore obviously the fault of the Russians, especially given how unhinged and paranoid rhetoric about Russia has gotten.
Yes, because the CIA would never lie to us, right?
They would never poison a Russian ex-spy to make Putin look bad?
I don't think this attack was orchestrated by a US entity. Or Russian for that matter. But when an entity that's hell-bent on controlling the worlds information gives a blanket statement about something without proof, I can only assume it's a lie.
It's easy to find information on bad things the CIA did [1], "minor" things of note including classic hits like "imposing a dictatorship in Iran, leading to an Islamic fundamentalist revolution and thus creating a powerful enemy against the US where there wasn't one before" and "trafficking drugs into the US and greatly amplifying America's drug problems", but looking for times where they actually did good for the country leaves me with little if anything.
The CIA's actions aren't done in national defense. They're a subversive organization. The fact the CIA suddenly shifted from being a shadowy government organization that people pretty much only knew about through action movies to being "open" about their ongoing activities within these past few years raises some red flags. Looking at the CIA's history, it's incredible that anyone would sit there and think they're trustworthy. I encounter people trying to say "well that's in the past" pretty often, which is a silly position to take, because why would they have any reason to stop?
I just read Shah of Shahs and I think it was a great little introduction to modern Iran and where the deep-seated resentment of the United States in Iran comes from.
I guess you know more than the CIA