So full credit to Rick Perry, the former Texas Governor, who led the pack in saying even before the weekend that Mr. Trump lacks the temperament to be Commander in Chief. Several other candidates have now said the same.

But note the silence of Ted Cruz, who declined to criticize Mr. Trump because he said the media enjoy such intra-Republican fights. Mr. Cruz has recently released a book whose main theme is an attack on other Republicans. It’s central to his campaign strategy. The Texas Senator must be hoping to inherit Trump voters once the casino magnate flames out, but he’s revealing his own lack of political character.

As for conservative media elites, too many have adopted the view that there can be no adversary to their right. This was mainly a left-wing affliction in the last century as many liberals refused to condemn Communists. But today many on the right seem willing to indulge any populist outburst no matter how divorced from reality or insulting to most Americans. If Donald Trump becomes the voice of conservatives, conservatism will implode along with him.