He would destroy her.
This campaigning style makes Hillary Clinton Donald Trump’s dream opponent. She gives him an endless amount to work with. The emails, Benghazi, Whitewater, Iraq, the Lewinsky scandal, Chinagate, Travelgate, the missing law firm records, Jeffrey Epstein, Kissinger, Marc Rich, Haiti, Clinton Foundation tax errors, Clinton Foundation conflicts of interest, “We were broke when we left the White House,” Goldman Sachs… There is enough material in Hillary Clinton’s background for Donald Trump to run with six times over.
Trump will capitalize on his reputation as a truth-teller, and be vicious about both Clinton’s sudden changes of position (e.g. the switch on gay marriage, plus the affected economic populism of her run against Sanders) and her perceived dishonesty. One can already imagine the monologue:
“She lies so much. Everything she says is a lie. I’ve never seen someone who lies so much in my life. Let me tell you three lies she’s told. She made up a story about how she was ducking sniper fire! There was no sniper fire. She made it up! How do you forget a thing like that? She said she was named after Sir Edmund Hillary, the guy who climbed Mount Everest. He hadn’t even climbed it when she was born! Total lie! She lied about the emails, of course, as we all know, and is probably going to be indicted. You know she said there were weapons of mass destruction in Iraq! It was a lie! Thousands of American soldiers are dead because of her. Not only does she lie, her lies kill people. That’s four lies, I said I’d give you three. You can’t even count them. You want to go on PolitiFact, see howmany lies she has? It takes you an hour to read them all! In fact, they ask her, she doesn’t even say she hasn’t lied. They asked her straight up, she says she usually tries to tell the truth! Ooooh, she tries! Come on! This is a person, every single word out of her mouth is a lie. Nobody trusts her. Check the polls, nobody trusts her. Yuge liar.”
Donald Trump is one of the most formidable opponents in the history of American politics. He is sharp, shameless, and likable. If he is going to be the nominee, Democrats need to think very seriously about how to defeat him. If they don’t, he will be the President of the United States, which will have disastrous repercussions for religious and racial minorities and likely for everyone else, too. Democrats should consider carefully how a Trump/Clinton matchup would develop, and how a Trump/Sanders matchup would. For their sake, hopefully they will realize that the only way to prevent a Trump presidency is the nomination of Bernie Sanders

