Mexican–American War Conclusion, Treaty of Guadalupe Hidalgo & Long-Term Consequences

Duration: $(17\text{ months})$ (spring $1846$ – autumn $1847$ )
U.S. deaths: $12,518$
- Disease: $11,000$ (≈ $88\%$ of all deaths)
- Combat: ≈ $1,500$
Early plan: prolonged occupation of Mexico City; cancelled when Gen. Winfield Scott was relieved of command and peace talks accelerated.
Lt. Ulysses S. Grant anecdotes
- Attended a bull-fight; called it “sickening.”
- Climbed Popocatépetl; described the descent as “one of the worst nights of my life.”

Mexican Army
- Primarily a conscription force (levy service; low morale).
- Officer corps inexperienced; few had formal training.
- Constant over-extension by Pres. Santa Anna (e.g., forced march of $(1{,}000\text{ mi})$ in $(23\text{ d})$ between Buena Vista and Cerro Gordo).
- Excelled in guerrilla tactics; harassed U.S. stragglers continuously.
U.S. Army
- Made up of volunteers, motivated by pay, patriotism, or Manifest Destiny.
- Officer cadre seasoned by the War of $(1812)$ and multiple Indian wars (e.g., Battle of Fallen Timbers).

Signed: $02/02/1848$ (Guadalupe Hidalgo, near Mexico City).
Lead U.S. negotiator: Nicholas Trist
- Thomas Jefferson’s relation; fluent Spanish; believed the war was unjust.
- Ignored Pres. James K. Polk’s recall order—decisive act that limited U.S. expansion.
Polk’s unrealized wish list (in green on lecture map): Baja California, Sonora, Chihuahua, Durango, Sinaloa, parts of Jalisco—essentially all Northern Mexico.
Senate dynamics
- Whigs (mainly North): opposed any treaty enlarging slave territory.
- Some Southern Democrats: feared admitting a large “non-white” population.

Mexico ceded $51\%$ of its land mass (today’s CA, NV, UT, AZ, NM, & parts of CO, WY, TX).
U.S. paid an indemnity of $\$15{,}000,000$ (Grant felt this was an over-payment).
Geopolitical shift: U.S. confirmed as a continental, overtly imperial power; Manifest Destiny “sea-to-sea” realized.

Gold discovered in California (January $1848$ , weeks before treaty ratification).
Pre-gold population figures: $7,000$ foreigners, $7,000$ Californios, $150,000$ Indigenous.
Gold Rush becomes one of the largest internal migrations in U.S. history, rapidly making California an Anglo-dominated state.

Article V
- International boundary set at the Rio Grande (Rio Bravo). Resolved original Nueces/Rio Grande dispute; created one of the world’s longest borders.
Article XI
- U.S. pledged to police border & halt Comanche raids into Mexico.
- Quickly proved impractical & ruinously expensive; Washington later ignored commitment (no “wall” against Comanche).
Article IX
- Promised “all the rights of citizens of the United States” to Mexicans in ceded lands.
- Reality:
- Property protection hollow; owners forced to defend titles in unfamiliar courts.
- Only $6\%$ of New Mexican land grants confirmed; taxes & legal fees became tools of dispossession.
- Created a landless Mexican under-class, blocking generational wealth—parallel to freedpeople denied “ $40$ acres & a mule.”
- Blacks & some Native peoples who were citizens under Mexican law lost citizenship status under U.S. racial codes.

Systematic stripping of voting rights; Mexican-American political participation plummets late $1800s$ .
Racial violence: spike in lynchings and mob attacks along the border around $1900$ .
Persistent anti-Mexican rhetoric echoes into the 21st century (“bad hombres,” etc.).

“Filibuster” = private military adventurer seeking conquest.
William Walker (Tennessee-born, pro-slavery doctor-lawyer-journalist)
- $1853$ : Invaded Baja California & Sonora; proclaimed Republic of Lower California/Sonora; became “president.” Expedition collapsed from desertion & starvation; returned $1854$ .
- Tried for neutrality violations; acquitted.
- $1855$ : Entered Nicaragua with $60$ men during civil war; declared himself president, reinstated slavery.
- Expelled $1857$ ; U.S. Navy briefly detained him, released.
- $1860$ : Final attempt in Honduras; captured by British Navy, handed to Hondurans; executed by firing squad.
Legacy: Model for a Caribbean/Latin-American slave empire; many ex-Confederates later sought refuge or ventures in Mexico after $1865$ .

Year: $1917$ .
German Foreign Minister Arthur Zimmermann sent coded offer to Mexico:
- If Mexico allied with Germany & attacked U.S., Germany would help reconquer the $1848$ lost lands.
Intercepted by British, forwarded to U.S.; sensational U.S. press coverage.
Provided major rationale for the U.S. abandonment of neutrality & entry into World War I.

$2008$ Absolut Vodka ad: Map depicting southwestern U.S. as part of Mexico, captioned “In an Absolut world.”
Highlights hypothetical: global history without the eighth & ninth largest state economies (CA & TX) in U.S. jurisdiction.
Concept names
- “Greater Mexico”: territories once or still culturally Mexican.
- “México de Afuera”: the Mexico abroad—diasporic communities north of the border.
Despite conquest & dispossession, the region retains enduring Latino/Latinx cultural identity.

War framed later as an unjust aggression; Trist, Grant, many Whigs & modern scholars concur.
Demonstrates how legal promises (Article IX) can be nullified by structural power disparities.
Example of racialized property law producing inter-generational poverty—case study paralleling African-American Reconstruction failures.
Provides background for current debates on immigration, border policy, reparations, and historical memory.