Carried by Florida and Louisiana.

The United States has 4 significant maritime features: the Atlantic coast, the pacific coast, the Great Lakes (sometimes called the north coast), and the Mississippi which is a river that is able to stand next to the Amazon and Nile, but is surrounded by arable and hospitable land.

For the Atlantic coast the major ports are largely in the northeast, florida, and Louisiana. They’d be able to build up South Carolina I’m sure, and if they need to can probably build up Alabama and Mississippi. But no real issues because they’d have Florida and New Orleans.

The Pacific coast is California, Oregon, and Washington( with its major ports being some of the bluest cities in the country. Though the non contiguous states are both pacific, but alaska swings and is contrary and Hawaii is blue and in the middle of the ocean. That’s irrelevant though because they’re accessed by air and sea. They get nothing there snd would rely on the Panama Canal.

The Great Lakes are a blue region. Michigan swings, as does Wisconsin, but the bluest part of Ohio aside from Columbus is the northern coastline (obviously especially Cleveland), the bluest region of Indiana is their northern coastline, and every other Great Lakes state is either blue or swing. And thanks to canals the Great Lakes allow for goods to be sent to the ocean, but it’s through the northeast so in a hostile situation Indiana and Ohio are basically landlocked. I imagine because of that Wisconsin and Michigan would go blue. It’s just too advantageous to not (similar to Kentucky and Maryland in the civil war)

The Mississippi is where they’d thrive. Louisiana is a major hit to the blue states here, the Mississippi is one of our country’s best economic features, and they’d be getting most states that border it, which doesn’t matter because they’d also be getting the outlet. The trumpistani economy would more or less be entirely dependent on it. And blockading the Mississippi is not only an obvious thing to do if civil war, it’s something the north did in the last one

Pretty much all in Blue states - the Red states have no pacific access and lode out on the eastern megacity.

Depends on how long hurricane season is. And how much more powerful hurricanes will get.