Largely overshadowed by the allegations against Trump has been WikiLeaks' day-after-day release of thousands of hacked emails from the Clinton campaign. The emails include excerpts of Clinton's closed-door speeches to Wall Street interests and lots of campaign strategizing over how to contain the political damage related to her handling of classified emails and her use of a private email server.

Trump has responded with a scattershot series of criticisms about "Clinton corruption," but he has yet to hone a disciplined line of attack. Wednesday night gives him a fresh opportunity to try to synthesize his message and find a way to make the email controversy stick.