New Delhi, July 16 -- ATLANTA - In the second minute of injury time, Lautaro Martinez met Lionel Messi's cross with his head, the ball arrowed inside the near post, and England's first World Cup final since 1966 was gone. Argentina 2, England 1. New Jersey awaits. The Falklands banner came out before the players reached the touchline.

Lisandro Martinez and Giovani Lo Celso unfurled a flag reading "Las Malvinas son Argentinas" in front of 68,239 spectators at Atlanta Stadium on Tuesday night. Within hours, what had begun as football's most charged semifinal in a generation had turned into a full diplomatic incident.

Peter Kyle, the UK Business Minister, described the display as an "egregious violation" of FIFA rules, which prohibit polit...