Panama promotes itself “as the bridge of the world, heart of the universe” but lately the narrow Central American Isthmus and its namesake canal that joins the Atlantic to the Pacific have become the setting for a bitter clash between the world’s two preeminent economic superpowers.

Panama and the US appear to have agreed to let American warships use the Panama Canal, effectively for free. Panama's strategic value-- to the US and many other shipping nations-- is thanks to its 51- mile canal,