I have yet to post on the Sarah Polk episode on CSPAN (hopefully this weekend, I will get caught up...), but the two guests were sparring over Polk and the Mexican War. You could tell the two guests (Conover Hunt and Paul Finkelman) did NOT agree on the Mexican War. Finkelman saw it as a unwarranted aggression well Hunt was more of the opinion, it was done, probably necessary to our success as a country. So anyway here's some information on the war, so you can make your own opinion!
Here is some background information:
What Polk wanted was to push Mexico into negotiating with the United States, and he was willing to create a threat of war to do this. If he had to fight, he wanted a short war and a quick victory. He never expected a long-drawn-out war. The Army was not ready for war and had never fought so far from home before. The country was divided. So Polk was taking a considerable risk in his bold stand toward Mexico.
Negotiations might have been possible if Polk had tried a different approach. Mexico had refused to recognize either the independence of Texas or its annexation by the United States, and when annexation occurred, broke relations and withdrew its minster from Washington. Polk rightly believed that he had to restore diplomatic relations, so he sent a special temporary envoy to Mexico. The Mexicans expected that envoy, John Slidell, would offer an indemnity to settle the Texas question, after which Mexico would receive him or someone else as permanent minister. Instead Polk made Slidell permanent minister and instructed him to open negotiations for the sale of California, ignoring Texas completely.
This did not suit the Mexicans at all. If they started by making a concession on Slidell’s status they would probably never get any settlement on Texas. Also Polk had backed up Slidell by sending troops to the Rio Grande, which Texans claimed was their proper boundary. The Mexican president, José Herrera, was newly in office and not very powerful. He did not dare receive Slidell for fear of being overthrown, as the opposition press was accusing him of planning to betray the country by selling Texas. Since he could not be received, Slidell left Mexico City for a town a few miles away, and Herrera sent troops to the Rio Grande to confront the Americans. Matters had reached an impasse.
Polk now needed an excuse to declare war, expecting at the most to fight a few skirmishes on the Rio Grande and then start negotiating. The Mexicans gave him the excuse he needed. The general commanding their troops on the Rio Grande sent a force across the river, and it ambushed a detachment of Americans and killed or captured all of them. The American general, Zachary Taylor, reported this action as a Mexican attack and concluded: "I presume this means the beginning of war." Polk and his cabinet prepared a declaration of war. Congress, badly divided between war and peace, had to support American soldiers under attack and voted to send supplies and reinforcements, whereupon Polk’s Democratic supporters convinced them that they might as well declare war altogether.
But Polk still did not expect the Mexicans to put up much of a fight. When his brother in Europe learned of what had happened, he wanted to come home and enlist, but Polk told him not to, as the war would soon be over.
The treaty itself was done after Polk recalled the diplomat:
With Mexico's capital in American hands, Polk sent diplomat Nicholas Trist to negotiate the terms of Mexican surrender with yet another new government, this one having overthrown Santa Anna after his loss of Mexico City. Expansionist fever at home in his own party pressured Polk to wring every possible concession from Mexico. Some even called for the annexation of "All Mexico," although all Polk really wanted was California. Trist resisted Polk's instructions, however, and so the President recalled him. In spite of this, the diplomat continued to negotiate with Mexico, and on February 2, 1848, he signed the Treaty of Guadalupe Hidalgo, which authorized U.S. payment of $15 million for California and New Mexico, and named the Rio Grande as the Texas border.
With the treaty in hand, Polk wisely decided to submit it to the Senate. After a short debate, the Senate approved the treaty on March 10, 1848, by a vote of thirty-eight to fourteen. Half of the opposition came from Democrats who wanted more Mexican territory, and half from Whigs who wanted none at all. Mexico, in what was called the Mexican Cession, ceded over one-third of its territory to the United States, increasing the latter's size by one-fourth. This Mexican Cession now contains the present-day states of Arizona, Utah, Nevada, California, much of New Mexico, and portions of Wyoming and Colorado. Just before leaving office, Polk created the Department of the Interior in an effort to help organize and administer these vast new western lands.