New Orleans is potentially the most important city in the world, as it is the gateway to the middle third of North America. From New Orleans, importers can reach the heart of the American market; for the American Midwest, the city is the gateway to a hungry world.
New Orleans also is a critical point for internal distribution. From New Orleans, it is a short hop to the Intracoastal Waterway – a narrow body of water sandwiched between the U.S. mainland and a long series of barrier islands that stretch all the way from the Mexican border to the Chesapeake Bay.
New Orleans is absolutely worth fighting a war over. In the 1830s, the United States backed the Texas rebellion against Mexico in the hopes of achieving some strategic depth for the city of New Orleans. That strategy nearly failed when Santa Anna’s forces nearly overran the Texican forces. The surprise victory over the Mexican army at San Jacinto, however, not only secured the city, but also set the stage for the American-Mexican war of a decade later that resulted in the Americans annexation of the entire northern half of Mexico, including territories that include contemporary California, Arizona and New Mexico.
For more, see Chapter 4 of The Accidental Superpower.