It shouldn't, America is two very distinct nations. The shape and nature of those nations vary wildly in classical Baudrilliardian sidewinding progression, but it's rooted in the very early history of British North America. Two distinct primogenitor colonies and societies, Jamestown and Plymouth. Founded for different reasons, in different contexts, by different people. Understanding the disparity is key to understanding a great deal about America. This divide has always persisted. Jefferson was of Tidewater, Hamilton was of Yankeedom. Democrats vs Whigs. Dixie vs Yankeedom. This split persists in history, and is much the reason why America is ostensibly a two party system. Even if the regional divide is not as hard and fast as it once was, even if the matters in which they differ change radically over time, the divide itself will always persist. It's wrapped up in the pre-revolutionary context the country was founded on. America will always be two countries in a trenchcoat, two echoes of wildly different cultures set against each other for dominance. You should always be keen to remember that. The union isn't of 13 distinct colonies, but two distinct cultures always in tension. It's a fundamental structure within our larger cultural blueprint.