That doesn't mean he shouldn't use every opportunity to hammer her on this.
But he doesn't. He gives her some Mad Magazine name like Crooked Hillary, mumbles something about her, and then changes his mind for the 18th time about what his immigration plan may be like from a digital, hypothetical, brick, licorice structure.
All he has to do, over and over: I'll cut taxes and then...HIllary corruption. Hillary emails. Hillary Benghazi. Hillary Iraq war. Hillary and her husband the sexual predator on kiddieporn flights. Hillary and her health. Hillary in hiding.
Then bring that to the debates, should they ever take place.
But no. He has idiot surrogates out there spewing stupidity while leaving you able to count the number of campaign offices he has in swing states on the hand of a bad wood shop teacher.