Why was the US military so unprepared to stop the Confederate rebellion in 1861?

Answer 1

The United States Military Academy at West Point had been graduating officers since the end of the Mexican War in 1848. The emphasis had remained on preparing its cadets for engineering, drilling techniques, and fortifications. The last war, being 13 years ago, had not improved on the strategies and tactics that were used by generals such as Winfield Scott. The war had been a short one and the opponent, led by Santa Anna, used the same approach to warfare as did Scott. Other than rehashing the tactics used in Napoleonic Era, and published by Henri Jomini, the US Military had made no progress or plans for engaging another enemy. Yes, certain West Point professors and graduates had produced military publications on fortifications and other military tactics, but not much beyond graduating good engineers had been the results. Between 1848 and 1861, no serious preparations had been made for fighting the "next war". In 1861, the only visible "enemy" were unsophisticated Native Tribes. And, to contain and relocate the American natives did not require anything more in terms of military strategy, than that of the most basic forms of fighting.Military theory was and remains an intellectually sophisticated and complex form of cultural expression. West Point did not advance in any manner to speak of, and unlike the warrior states of Europe, such as Prussia, military thinking in the US was stagnant. Each side in the US Civil War was unprepared to conduct a war against "themselves" in a manner of speaking. The generals and commanders of the Mexican War were now engaged in a war with former friends and classmates from West Point.