For one, the message the US intercepted from Germans, meant for Mexico for Mexico to declare war against the US
No. Ever.
There were a number of factors which caused that war to be.
Mexico
The desire for Texan Independence from Mexico.
Mexico
Mexico
The War against Drugs.
Yes, Lincoln was against the War with Mexico.
Mexico fought against the United States. It is known as the Mexican-American War (1846-1848)
Mexico won its war of independence against Spain in 1821.
1848. US troops under General "Blackjack" Pershing chased Poncho Villa into Mexico in 1916, but that was not a war "with" or "against" Mexico.