Give me one reason why the mexican-american war was not justified do research for this answer

In the Mexican-American war, the Mexican's were not prepared for the battle: they did not have a strong enough army to handle America and they were already falling apart.
 Source was History.com if you need more

The answer is society was a caste like system with poor whites at the bottom of the white social ladder.

It allowed for things to be produced much more quickly and efficiently