In an act of casual but consequential cartography, Donald Trump posted a map this week reimagining the western hemisphere as American territory — Iceland, Greenland, Canada, Mexico, Cuba, and Caribbean nations rendered in US colors without a word of explanation. Iceland summoned the US ambassador, Denmark and Mexico issued formal condemnations, and a small Nordic nation of 370,000 people found itself formally objecting to its own symbolic erasure. The episode is less a diplomatic crisis than a mirror held up to a deeper question: what does sovereignty mean when a powerful nation treats borders