The Mexican - American War (1846-1848)

Causes

The Texas Boundary

The Mexican government never recognized the Rio Grande River as the Texas boundary. They placed the boundary at the Nueces River to the Red River. A vast disputed territory lay between.

California, New Mexico, Arizona, etc.

Polk wanted to purchase these territories, and he intended acquisition of these lands however necessary. He wanted to counter his loss of prestige in backing down on the Oregon dispute and accepting the 49th parallel as the northern border. He was willing to pat 25 to 40 million.

John Slidell's Mission

Appointed as diplomatic minister to Mexico, with the special mission of settling the boundary dispute and the acquisition of the disputed territory.

The Mexican coalition government refused to even receive him, creating an international incident. Their reasons were that they had just gained power, and close contact or sell of territories at that point would have resulted in the collapse of their government.

General Zachery Taylor's Expedition

Polk reponded by sending General Taylor to the Rio Grande, into a territory that had been specifically named no-man's land by the Mexicans. Anyone entering this area was to be shot, and American reconaissance troops were.

Taylor reponded by immediately moving across the Rio Grande and occupying Matamoros, blockading the river. War is yet to be declared.

US Declaration of War (May 13, 1846)

President Polk had decided to declare war, but had to wait until the Mexicans started it. Thus Taylor's expedition. Congress deliberated for two days, then declared war.

The US put its support behind Santa Anna in return for the sale of the disputed territory once he was back in power.

Santa Anna failed to take the actions agreed upon. He was subsequently overthrown by Winfield Scott, and Mexico City was occupied.

Peace Negotiations

Nicholas Trist

Trist's mission was to extract a treaty acquiring the disputed territory. Polk did not like the consiliatory manner with which Trist handled the negotiations (and he didn't want a Whig war hero), and sent a letter withdrawing him, but it was too late. A treaty was nearly complete already, and Trist stayed to sign the document.

Treaty of Guadaloupe Hidalga (February 2, 1848)

The US paid $50 million for the disputed territory and got recognition of the Rio Grande as the Texas border. The American government would pay the war claims of American Citizens.

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