U.S. and EU—but Not Germany— Support Land Swap in Balkans

Washington and Brussels favor Serbia and Kosovo redrawing their border along ethnic lines, an approach Berlin says would open Pandora’s box

BRUSSELS—U.S. and European Union leaders are converging toward supporting a plan under which two Balkan countries would redraw their fraught common border along ethnic lines, isolating Germany, the continent’s most influential power, in its rejection of that approach, a confidential document shows.

A recent memo by the EU’s foreign service about how to solve a decade-old standoff between Serbia and Kosovo, reviewed by The Wall Street Journal, shows the EU’s executive body has essentially adopted Washington’s argument and...