Renewed U.S. attention to Greenland has reactivated debates on Arctic and North Atlantic security, particularly the Greenland-Iceland-United Kingdom (GIUK) Gap. This is re-emerging as a pillar of European security owing to: intensified reliance on transatlantic reinforcement since the war in Ukraine; NATO’s expansion to Finland and Sweden; and climate-driven Arctic ice melt, which enables greater naval access and a rising Russian operational presence.