They are democracies loyal to the liberal rules-based order. But Lithuania, Latvia and Estonia are soon to leave the international convention that forbids anti-personnel landmines, in order to harden their borders against potential Russian aggression. Another baleful consequence of the end of guaranteed American protection.

And speaking of baleful consequences, investors have bid up the share prices of the “Magnificent Seven” tech firms mightily in recent years. Now the mighty are trembling. The market chaos kicked off by Donald Trump is the proximate cause—but the reasons to worry run deeper, too.