Question

Why were many Americans in favor of going to war with Mexico? They knew the only way to annex Texas was to declare war on Mexico. They believed it was necessary in order to gain more territory. They needed territory where Native Americans from the East could be resettled. They thought that defeating Mexico would lead to the possession of Oregon.

Answer 1

One of the reasons why so many Americans were in favor of going to war with Mexico was because "They believed it was necessary in order to gain more territory," since it was clear that Mexico was not going to sell the land voluntarily. 

Answer 2

Answer;

They knew the only way to annex Texas was to declare war on Mexico.

Explanation;

At this time Texas was still connected to Mexico.

There were various reasons as to why the United states and Mexico went to war, but the most important ones were the US annexation of Texas and the Americans' desire for California and other Mexican territories

The United States won the war and Mexico signed the Treaty of Guadalupe Hidalgo in 1848.