Do the Democrats in leadership ever ask themselves: WWGOPD?
The GOP pounded Benghazi, emails, Uranium One, Clinton Foundation, etc., and made them stick with little to no actual bad underlying behavior. By being bold and relentless and working the refs, they fatally damaged Clinton's candidacy. With nothing.
What material do the Democrats have to work with? Oh, not a whole lot. Just that the POTUS welcomed help from a hostile foreign power, sought to weaponize the information stolen by that power, and has been sucking up to that hostile foreign power ever since. And he broke the law trying to cover that up.
The GOP manages to spin straw into political gold while the Dems have mastered the alchemical transmutation of gold into lead.