The Mexican-American War is considered a major turning point in US History because the result of the war added a lot of territory to the US land corresponding with Arizona, parts of New Mexico, Colorado, even Utah and southern California. When we talk about this historically, we call it the Mexican Cession. Southerners wanted to expand slavery. Under the terms of the Compromise of 1820, any states that were below a certain line were automatically admitted as slave states. Most of the territory that could be acquired from Mexico would have fallen under this line. There’s also those who support a policy called Manifest Destiny. This is the very influential idea that states that it was the United States’s God-granted mission to spread civilization and democratic government from ocean to ocean. Thoreau objected to most of these rationales.
Thoreau, as a transcendentalist, was highly individualistic and believed in individual conscience, or decision-making. He believed that the individual conscience was the person’s own highest law. In other words, a person had a strong duty to the conscience. He believed in this principle, he had a distrust of government in general as he believed that, when governments made decisions, they were taking away the individual’s discretion. In this essay, Thoreau defends disobeying written laws when they contradict one’s conscience. He was arrested for refusing to pay a particular tax, as he objected to the Mexican-American War because he objected to slavery and rejected the logic of Manifest Destiny. He calls out those who privilege their own narrow interests over what the conscience dictates they should owe humanity: ‘Practically speaking, the opponents to a reform in Massachusetts are not a hundred thousand politicians at the South, but a hundred thousand merchants and farmers here, who are more interested in commerce and agriculture than they are in humanity, and are not prepared to do justice to the slave and to Mexico, cost what it may.’ (Thoreau 19-20)
He emphasizes that the weakness of others in this regard is no excuse for faltering when it comes to your own conscience. Despite the material futility of his action, he had to do them anyway in order to satisfy his conscience. Despite to how far to take the second part of Thoreau’s philosophy, his position sounds real noble, but he bore his costs alone because he didn’t really have dependents and history suggests he was much less dependent on human relationship than the rest of us.