But how to get to the bottom of who did what?
One way would be to listen to the person who should know all about this stuff: Edward Snowden. This is what he said earlier today on Twitter:
“Even if the attackers try to obfuscate origin, #XKEYSCORE makes following exfiltrated data easy. I did this personally against Chinese ops. Evidence that could publicly attribute responsibility for the DNC hack certainly exists at #NSA, but DNI traditionally objects to sharing. The aversion to sharing NSA evidence is fear of revealing “sources and methods” of intel collection, but #XKEYSCORE is now publicly known.”