Denmark Invokes NATO's Core Rule—Against the United States

At NATO's July 8 summit in Ankara, Denmark's Prime Minister Mette Frederiksen argued fellow members should defend Greenland from U.S. claims—invoking Article 5, collective defense, against an ally rather than an external threat. This has no postwar precedent. It exposes a gap in NATO's founding logic: the alliance was built for external aggression, not disputes within itself. Whether members will honor this claim remains untested.