I've already done photo diaries on my visits to Fort Brown, Matamoros, Palo Alto, and Resaca de la Palma, but since the Mexican War has been mostly forgotten in the US, I wanted to do a history diary to tie them all together.
In 1844, the central issue in American politics was Texas.
For several decades, the area of Texas (then a part of Mexico) had been steadily settled by immigrants from America-some of them legally, some not. By 1836, most of the population was American, and in an armed rebellion, the "Republic of Texas" declared its independence from Mexico and asked the United States to annex it as a state. But the Mexican Government continued to assert its claim to Texas, and the US, unwilling to provoke what might turn into a war and also entangled in a bitter sectarian argument over the admission of another slave state into the Union, declined to annex the territory. Mexico, meanwhile, was too weak to reconquer its rebellious province. The "Texas Republic" hung in limbo for ten years.
The controversy continued all the way into the 1844 Presidential campaigns. The Whig candidate, Henry Clay, argued in favor of delaying annexation for a time, pointing out that the US was not prepared to fight a war over the matter and hoping to reach some sort of compromise deal with Mexico. The Democratic candidate, James Polk, meanwhile, was an unabashed expansionist, and openly advocated not only the annexation of Texas into the United States, but a policy of obtaining all the land in the Mexican, British, and Native American territories in the west, either by purchase or by conquest, until the United States stretched from coast to coast.
Polk was riding a wave of popular enthusiasm for an ideology that was called "Manifest Destiny". This rather strange mix of religion and politics declared that the United States of America was God's favorite nation, the one He loved best-and as God's new Chosen People, the US had not only the moral right to possess all the territory that it could get in North America, but the divine right as well-it was what God wanted. By conquering the heathens and other inferior peoples of the West, American leaders piously declared, they were fulfilling God's Plan and manifesting their divine destiny.