There should be no doubt that the Russians (and several others) had the interest and the means to hack the DNC and Podesta emails (and many, many other high-value American government and corporate targets).
There should be little doubt that the Russians actually DID hack the DNC and Podesta emails.
There should be quite a bit of doubt that the Russians fed the content to Assange.
There should be a hell of a lot of doubt that the Russians wanted to swing the U.S. election in favor of Trump.
Edit to add:
There should be TOTAL DISBELIEF that Trump won because Russia hacked into our voting machines and changed the votes to his favor.
Just so.