Why Did We Go To War With Mexico In Mid-1800s?

One of the least known and least understood armed conflicts in United States history is the U.S.-Mexican War.

Why did we fight the war — a war, described by future president — and lieutenant in the war — U.S. Grant as “one of the most unjust ever waged by a stronger against a weaker nation.”

Simply put — we wanted their land.

It was the era of Manifest Destiny — that conveniently contrived notion that God wanted us to own all the land from ‘sea to shining sea’ — and President James K. Polk was fully on board with the concept. He decided to set the stage, provoke an attack (after we invaded Mexico) and then say to Congress, it’s a hostile situation, war is inevitable. According to Don’t Know Much About History by Kenneth C. Davis, it unfolded like this:

Treating Texas as U.S. property, (President James K.) Polk sent General Zachary Taylor into the territory with about 1,500 troops in May 1845, to guard the undefined ‘border’ against a Mexican ‘invasion.’ After months of negotiating to buy Texas, Polk ordered Taylor to move to the bank of the Rio Grande. This so-called army of observation numbered some 3,500 men by January 1846, about half of the entire U.S. Army. Escalating the provocations, Polk next had Taylor cross the Rio Grande. When a U.S. soldiers was found dead and some Mexicans attacked an American patrol on April 25, President Polk had all the pretext he needed to announce to Congress, “War exists.” An agreeable Democratic majority in the House and Senate quickly voted — with little dissent from the Whig opposition — to expand the army by an additional 50,000 men. America’s most naked war of territorial aggression was under way.

In 1848, the Treaty of Guadalupe was signed ending the war and setting the Mexico-U.S. border along the Rio Grande River. The United States gained nearly 500,000 square miles of land — including the area of future states: California, Nevada, Utah, most of New Mexico and Arizona, parts of Wyoming and Colorado, as well as Texas.

The treaty did force the U.S. to pay Mexico $15 million, causing one Whig newspaper to proclaim,

“We take nothing by conquest… Thank God.”

The comment reminds me of a joke a co-worker once said concerning George W. Bush’s preemptive attack policies which led to war in the Middle East.

“It’s not our fault God put all of our oil underneath their sand.”