Charles Krauthammer is a useful (to progressives) idiot. He puts the very worst spin on Donald Trump's words, just like leftists do. When an ordinary American hears Trump say that Hillary Clinton belongs in jail, he or she hears, "Nobody is above the law." When Krauthammer hears it, he hears, "I have adjudged her guilty and will send agents of the state to apprehend her and lock her up." This shows that an expensive formal education (Oxford University, Harvard Medical School) is compatible with linguistic incompetence and general stupidity.
What really rankles Krauthammer is that Trump will not be a warmonger like George W. Bush was or Jeb Bush would have been. Krauthammer thinks that Clinton is more hawkish than Trump, and therefore more likely to do the bidding of neoconservatives, so he is perfectly willing to live under a Clinton presidency for four years. That a Clinton presidency will make the lives of ordinary Americans worse rather than better doesn't bother him, for he and his family are insulated from such things as urban crime and decay, illegal immigration, and job loss due to globalization. I strongly suspect that Krauthammer has never been in a grocery store, hardware, or fast-food restaurant. He personifies the Washington establishment.