In OTL, General Winfield Scott and his staff joined Commodore David Conner on a ship to observe Vera Cruz. As one of those staff officers, George Meade, recorded, they drew fire from the Mexican Fort of San Juan de Ulua. Had those shots hit, Scott and Conner, leaders of the Army and Navy forces present would probably have died. So would all of Scott’s general officers and several members of Scott’s staff – Meade, Robert E Lee, Joseph Johnston, and PGT Beauregard. With this decapitation of US forces, at the very least the Vera Cruz landings could have been delayed and they might not have made it out of the lowlands before fever season crippled the army. Even if they had, without Scott’s abilities as leader and Lee’s abilities scouting, the US forces could very well have lost the war.