Carl von Clausewitz, a 19th-century Prussian general, described warfare as “the realm of uncertainty”. The fellow never had to deal with an American administration run by Donald Trump. Forget the fog of war Clausewitz posited; Europe is discovering the perils of wading through the haze of Pax Americana, MAGA edition. Wish it luck. Being the biggest trading partner of a country that seeks “liberation” through tariffs, or a decades-long military ally of a superpower now parroting Kremlin talking points, is akin to inching through a geopolitical pea-souper. Europe is hardly alone in being flummoxed by Mr Trump (many Americans are, too). But it faces a unique problem: Europe cannot fathom what it should do to fix its already broken relationship with the new administration. Even if Europeans wanted to help their historical partner—a big “if” these days—disagreements abound as to what that partner wants.