Treaty of Guadalupe Hidalgo

19 May 1848, at Querétaro

On 19 May 1848, meeting at Querétaro while U.S. forces occupied Mexico City, Mexico's Chamber of Deputies approved the Treaty of Guadalupe Hidalgo as amended by the United States. The vote was 51 in favour and 35 against, after an intense debate over accepting the territorial settlement or continuing the war.

The U.S. Senate had sent the February treaty back with amendments, deleting Article X and modifying other provisions. Mexico's government — defeated, financially exhausted and displaced from its capital — put that amended text to Congress as the alternative to renewed fighting.

Not ratification, not yet

The deputies' vote did not finish the process. The Mexican Senate still had to approve their resolution, and did so several days later, 33 to 4.

On the same 19 May, Foreign Minister Luis de la Rosa moved preparations along by asking the U.S. commissioners, Nathan Clifford and Ambrose Sevier, to come to Querétaro.

Presidential ratification and the exchange of ratifications at Querétaro on 30 May still lay ahead.

What the deputies were accepting

The treaty promised Mexico US$15 million, and the United States assumed up to US$3.25 million in specified claims held by U.S. citizens against the Mexican government. More than 525,000 square miles were added to the United States.

Article VIII let residents who stayed in the transferred territories formally elect to retain Mexican nationality; moving away was not the only way to remain Mexican.

The original treaty had been signed at Guadalupe Hidalgo on 2 February by Nicholas Trist, who negotiated and signed it after President Polk had recalled him. What the deputies were voting on was not that text but the version the U.S. Senate had since amended, with Article X struck out.