Lonely Choices: The Treaty of Guadalupe Hidalgo and the Time We Took 55% of Mexico

February marks the anniversary of a peace treaty that literally changed the American landscape.  It was a treaty that ruined the career of its US negotiator, Nicholas Trist, but nevertheless, cements his name in history as fundamentally changing the shape of the United States as we know it. 

Records of the U.S. House of Representatives.
National Archives Identifier: 2127339

On February 2, 1848, the Treaty of Guadalupe Hidalgo was inked and ceded nearly 55% of what was then Mexico and are now parts of Arizona, California, New Mexico, Texas, Colorado, Nevada and Utah, to the US for $15 million and an end to the fighting in the Mexican-American War. 

After three years of battles and numerous attempts to renegotiate the border with Mexican dictator, Antonio Lopez de Santa Anna, by September 1847, US troops finally defeated Santa Anna and the Mexican army and were occupying Mexico City.  

Let’s think about that for a second.  At one point, the US occupied Mexico City!! That is pretty phenomenal to consider.  I personally live in the Houston, Texas area and Mexico City is 936 miles away, which is a 17 hour car ride without stopping, in case you were wondering.

It’s an interesting part of our history that we don’t often think about.  That in a time before cars and airplanes, our troops, many of whom were likely from the northern states, had to go all the way down to Mexico City to fight a war.

Now at the time, US President Polk and other members of Congress, wanted not only the parts of Mexico delineated on the map shown above, but also wanted Baja California, and were willing to pay up to $30 million for the entirety of it. In Polk’s eyes, his negotiator, Nicholas Trist, who was the chief clerk of the US State Department at the time, betrayed his wishes and acted in defiance of the president when he sat down with the new Mexican government (sans Santa Anna) and negotiated a smaller amount of land for $15 million.  Polk had sent a message telling Trist to come back to Washington and abort the negotiations, but Trist carried on.

In a letter to his wife in December 1847, Trist said, “Knowing it to be the very last chance and impressed with the dreadful consequences to our country which cannot fail to attend the loss of that chance, I decided today at noon to attempt to make a treaty; the decision is altogether my own.”

Nicholas Trist, photo by Mathew Brady, Public domain, via Wikimedia Commons

In fairness to Polk, it doesn’t make sense even today that Baja California is still a part of Mexico but is attached geographically to the US. However in fairness to Trist, he probably had a better idea of what it would take to get the deal done with the newly formed Mexican government.  As his quote above suggests, there were real consequences to delaying and real lives on the line. 

In the end, Trist was fired by Polk, yet Polk and Congress also ultimately decided to ratify the peace treaty to move it forward rather than reopen the matter.  The US ratified the treaty in March 1848; Mexico in May 1848 and US troops were pulled out of Mexico City by August 1848.

Trist never recovered politically even though he was married to Thomas Jefferson’s granddaughter and had served as his personal secretary.  He later supported Abraham Lincoln’s election, but had no role in his administration.  Despite his connections, he ended up back in his home state of Virginia, but was later appointed Postmaster General in Virginia during the presidency of Ulysses S. Grant.

In December 1848 in an address to Congress, President Polk said of US/Mexican relations, “The amicable relations between the two countries, which had been suspended, have been happily restored, and are destined, I trust, to be long preserved.”

It’s interesting to think about what the US would look like today if Baja California had been procured and also interesting to think about Trist’s reasoning for taking the smaller portion.  Either way, the peace treaty made all of the difference in how the US would ultimately take shape.

For more resources on the Treaty of Guadalupe Hidalgo and it’s players, visit these resources: