Mr. Trump’s foreign-policy stance operates on two levels and he has it backward.: America First isolationism in content, slotted within an ardent anti-establishment, anti-expert frame. The two are inextricable — in Mr. Trump’s world, the foreign policy elite in both parties have forced us into expensive alliances and wars. Get rid of them, and America will be great again. As much as his neo-isolationism frightens our allies, it is Mr. Trump’s anti-establishment stance that most threatens international security. No doubt, the modern foreign policy establishment can be criticized for stale or lazy thinking, or parochial self-interest. But it still includes many men and women with a sophisticated knowledge of the world. To ignore them and their counsel is foolish.