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

Ifound this information on google “agriculture is important, as are manufacturing, tourism, and a strong geothermal energy resource base. the economy has been expanding since 2010.” i hope this