[sqeaky]

Proof will likely never come and those news outlet sources are the intelligence experts saying so. All the intelligence experts say they cannot prove it, all except one group believed it was Russia. Comey was particularly vocal about it.

This is the kind of thing we might never get objective proof of, hacking is too easy to cover up or contract out. In cases like this where not acting could be detrimental and we already have an enemy we were acting against attributing malicious activities to them is reasonable. Trying to screw with your enemy's government's transitions of power is a common tactic at least since the early cold war.

If you had asked me 5 years ago when relations were better and before Putin got all Ukraine and Syria crazy, I would have said "I don't know, it is too premature to act". But right now Russia feels threatened by us and sees weakness in our elections this makes them hacking us fit too well. With that being as close to proof as we are likely to get it is the information we have to work with.