Why did some people oppose the war with Mexico?

Answer 1

A Mexican cavalry unit crossed the Rio Grande and ambushed an American patrol, killing or wounding 16 American soldiers. Two days later, Congress declared war, and the War with Mexico began. Not everyone favored war. Some people felt that the conflict was unjust and did not see the need to declare war.

Answer 2

Not really sure which war with Mexico you're talking about, I'm going to go ahead and assume you mean the 1846-48 Mexican-American War.

Basically, a lot of people in the North and in the Whig Party (which would later become the core of the then-new Republican Party) felt that the war was an attempt by the South and Democrats to conquer ill-gotten land in the hopes of expanding slavery (which Whigs/Republicans strongly opposed). Some Southerners even expressly stated that they hoped that slavery would indeed spread to newly conquered territory in Mexico.

Answer 3

Because the war was promoted by pro-slave interests; the lands acquired from Mexico would be a flagrant attempt on expanding slave territory. This conflict with Mexico actually planted the seeds for the American Civil War (1861-1865)

Answer 4

They grown to oppose the war because there was a great deal of suffering involved and they were worried about slavery.

Answer 5

It had all the makings of a War of Conquest.

The casualty count as a result of Yellow Fever was unacceptable.