for what reason did some americans support and some oppose the war with mexico in 1846?

Answer 1

Those who supported it did so because they were greedy and immoral and hateful people, almost devoid of conscience, with an anthropocentric view of the world, and with the firm belief that Mexicans and Indians and ***** slaves weren't men, and so killing them and taking their land and possessions was perfectly acceptable. Those who opposed it did so because they were somewhat less greedy and immoral and hateful than the rest.

Answer 2

The US has engaged in a number of immoral wars, though our history books deny it. Possibly the most immoral was our unprovoked attack on Iraq; for second I nominate our newspaper-provoked attack on Spanish colonies; for third, see the 1914-18 Great War.

But for fourth, I have the 1846 US attack on a disorganised and defenceless Mexico. This is not to deny the competence and bravery of US troops in that war, regular and volunteer, who often defeated Mexican forces many times their size, nor the bravery of ill-lead Mexican soldiers, who so often proved better to die than their leaders were to lead.

In this case, though, southern leaders were looking to add more slave territory to the southern end of the country. We did add a great deal of volume through this immoral war, but it ultimately did not help the slave owners.