Regarding Robert Lee and the siege of Veracruz:
US President Polk contrived war with Mexico because he wanted a port on the Pacific to compete with European nations in the plunder of Asia. Not only did Mexico not recognize the independence and later US annexation of Texas, but the two sides disputed the location of its southern border. Mexico (rightly I believe) claimed the border was the Nueces River, but Polk claimed it was the Rio Grande, or Rio Bravo as it is called in Mexico. A small party was sent south of the Nueces. Inevitably, it was attacked, in a pathetic little skirmish. This was the pretext Polk had sought for war. It would result in the loss of nearly half of Mexico’s total territory. Spanish speakers in the annexed areas became the first Chicanos. Antonio Burciaga said, “We didn’t cross the border, the border crossed us.”
Winfield Scott commanded a force that would march to Mexico’s capital via the Veracruz Road. Veracruz was a port city defended by strong walls and fortifications. To overcome this, Scott landed on the shore south of the city and besieged it with cannonry. This is sometimes called the first instance of impersonal modern warfare. The attackers mostly ignored the walls and instead lobbed massive shells over them indiscriminately. Women and children sought shelter in churches, historically havens during combat, but the attackers did not discriminate among targets. Nearly 7000 shells were launched over the course of four days. There were countless civilian casualties, and entire sections of the city were leveled.
Robert Lee was the engineer in charge of the bombardment. He positioned the cannonry and charted the arcs of the shells. He later said, “The shells from our battery were constant and regular discharges, so beautiful in their flight and so destructive in their fall. It was awful! My heart bled for the inhabitants. The soldiers I did not care so much for, but it was terrible to think of the women and children.”
This story is told in "The US-Mexican War," a book Carol Christensen and I did to accompany a PBS series back in the 1990s.