The interesting question is, "What comes next?"
Yes, Trump is an egotistical blowhard who shoots from the hip, often without thinking or collected the information he needs. The thought of a nuclear-armed Donald Trump playing brinkmanship with a nuclear-armed Kim Jong-un should terrify any thinking adult. Yet for all of his flaws, he is not entirely stupid -- the world is full of egotistical blowhards who never escape anonymity. My guess is that Trump will see that the most important thing for him to do after securing the nomination will be to try to restore party unity by choosing a running mate who will soothe the GOP establishment and, hopefully, compensate for his lack of experience. The choice would have to be someone credible, but his pride probably rules out anyone who has been a noteworthy critic during the election cycle.
My suggestion would be Condoleezza Rice. She is not a natural politician, by which I mean she does not have the personality to schmooze comfortably with people of all backgrounds, but she is strong in areas where he is weak.
- She is not Oprah Winfrey, and she will not be able to deliver majorities of either the black vote or the women's vote, but because Trump has so far made his appeal mostly to middle class, middle aged, angry white males, he urgently needs the help of someone like Rice to appeal to a wider demographic field.
- Trump has already made a mess of his foreign relations, and he has not even won his party's nomination. The British parliament seriously considered banning Trump from the UK, he had a quarrel with Pope Francis in February, he has called NATO obsolete -- an idea I agree with, basically, but it should not be handled this clumsily -- and of course the signature piece of his campaign has been bullying Mexico. If he is ever to govern, he must have on his team someone with more knowledge, experience, and temperament for international relations, and he must listen to that person. Rice would be perfect for this.
- What Trump really, really, really should do is make Condoleezza Rice his running mate and then announce, a week or so after the GOP convention, "I've been talking with Condoleezza, and she made a very good point. A wall doesn't have to be made of stone or brick, and a fence doesn't have to be made of wood or steel. All we really want is something that will effectively deter illegal immigration. This can be done by persuading Mexico to greatly enhance their own border patrols. This would be a 'wall' Mexico could pay for without having the money leave their nation, and it would respect both our sovereignty and theirs. This is the wall I intend to see built."
This would bring him back into the world of the actually possible, which would reassure a lot of nervous voters and put him in a less confrontational position should he actually be elected. Even more importantly, it would show he will listen to reason and can be persuaded -- even by (gasp!) a woman.
For Hillary Clinton, the road is much easier. She is far from an ideal candidate herself, as the Sanders campaign has demonstrated, and her sloppiness with classified emails is being investigated at a very inopportune time for her, but ultimately I expect her to be at the head of a party that will unify in opposition to Trump. She can pretty much guarantee a win if she takes Florida, and I think Charlie Crist could help her do that.