Penn State historian Amy Greenberg says it was the first war in U.S. history that was fought for greed rather than principle: "There was no great ideological reason why we were going to war against Mexico. It was the first war that was started with a presidential lie."
Greenberg argues in her recent book, "A Wicked War," that the war was engineered by President James Polk.
"James K. Polk went to Congress and said American blood had been shed on American soil, but almost nobody except Americans claimed that the land where the blood was shed was actually American soil," Greenberg said. "When Zachary Taylor marched his troops between the Nueces and the Rio Grande, he was marching through land which everybody, including the residents of that territory, believed to be Mexican land."
"So they were basically looking for a fight?" asked Rocca.
"Absolutely. No question about it."
They were looking for a fight because President Polk had a vision for America called "Manifest Destiny."
Link to Amy Greenberg's book: "A Wicked War"