The assumption that the person who leaked this document is somehow “smart” must also be thrown away. “Smart” people do dumb and stupid things all of the time. If you have no morals you will do very dumb and immoral, unethical and illegal things - this is why I believe it was a left-wing clerk.
I'm with you. The Left is notorious for leaks, and there's plenty of history and/or receipts to prove it. In fact, they LOVE doing this sort of thing, and relish in the notoriety, even if it costs them their career.
It was definitely a leftist.
This was a political move to fire up the democrat base going into the midterms.