3Manifest Destiny Settlers began flocking west in search of cheap land “(It is) ...our manifest destiny to over spread and to possess the whole of the continent which Providence has given us for the development of the great experiment of liberty.”John O’Sullivan, editor of the “The Morning Post,” 1845
4TexasUS foreign policy of expansion (Manifest Destiny) soon put it in conflict with MexicoAmerican immigrants moved to Texas when it was still a province of Mexico and began clamoring for independenceAfter initial setbacks at the Alamo and Goliad, the Texans defeated the Mexican Army at the Battle of San Jacinto on April 21, 1836 and Texas declared its independence from MexicoBefore he left office, President Andrew Jackson extended diplomatic recognition to Texas but, fearing war with Mexico, refused its request to be annexed to the US
5TexasJackson also knew that annexing Texas, a potentially huge area for the expansion of slavery, would hurt fellow Democrat Martin Van Buren’s chances of election in 1840Nonetheless, Jackson privately urged Texans to seize harbors on the Pacific Coast which made annexation more attractive to commercial interests in the northeastAndrew Jackson
6TexasWilliam Henry Harrison ran for President as a Whig and defeated Van BurenThe strongest Whig areas were in the New England and Great Lakes area so Harrison balanced his ticket regionally with Virginian John Tyler as a vice-presidentWhen Harrison died of pneumonia in April 1841, barely a month after his inauguration, Tyler became presidentHarrison
7TexasTyler was a former Democrat who had left the party over Jackson’s issuance of the Force Bill during the Nullification CrisisTyler’s agenda strongly supported the South and state’s rightsHe began distancing himself from the Whig agenda and renewed the annexation of Texas issue to gain favor with southern and western DemocratsJohn Tyler
8TexasTyler replaced Daniel Webster as secretary of state with pro-annexation Virginian Abel Upshur and secretly opened negotiations with the TexansAfter Upshur died, John Calhoun became secretary and completed the negotiations and made the protection of slavery a highly visible issueCalhoun saw the annexation of Texas as a security issue for the United States and accused the British of conspiring to force emancipation on Texas and destroy slavery in the South
9TexasCalhoun’s rhetoric convinced antislavery northerners that the annexation of Texas was part of a southern plan to expand slavery and political powerThe Senate rejected Calhoun’s treaty of annexation by a two-to-one margin in June 1844, but the debate continuedJohn Calhoun
10TexasIn the Election of 1844, Van Buren’s anti-annexation stand cost him the Democratic nominationInstead it went to James Polk, a compromise choice from Tennessee who favored expansion (both in Oregon and Texas)Tying Oregon to the expansion package helped protect the Democrats from being accused of being too prosouthern
11TexasPolk defeated Whig candidate Henry Clay by less than 2% of the popular vote, but Tyler still took Polk’s victory to be a mandate to annex TexasRather than putting the matter before the Senate where he knew he could not muster the necessary 2/3rds majority, Tyler used a joint resolution of Congress to invite Texas to join the UnionMexico, of course, did not consider the annexation legitimate
12Diplomatic Machinations Eve of Mexican War Many Americans, including Polk, had expansionist designs not only in Texas but on Upper California and New Mexico as wellMexican authorities had only tenuous control of these areasPossession of San Francisco would give the US a valuable harbor to support trade with the Far EastDemocratic Senator Thomas Hart Benton of Missouri was a key proponent of gaining Pacific Coast harbors to further trade with India and China
13Diplomatic Machinations Eve of Mexican War Polk dispatched John Slidell to Mexico City with an offer to purchase California and New Mexico and to secure the Rio Grande as the Texas boundaryThe Mexicans considered the Nueces River to be the border between Texas and Mexico while the Texans considered it to be the Rio Grande
14Diplomatic Machinations Eve of Mexican War Slidell landed at Vera Cruz on November 29, 1845 but Mexican foreign minister Manuel Pena y Pena announced he would receive Slidell only as a “commissioner” rather than as a full-fledged “minister”The Mexicans felt that granting Slidell status as minister would give credence to the American claim to Texas and weaken General Jose Herrera’s government
15Diplomatic Machinations Eve of Mexican War Slidell arrived at Mexico City on December 6, but the Mexicans refused to meet with him as long as he insisted on being considered a ministerIn January 1846, Slidell notified Polk that he had given up on a diplomatic solutionJohn Slidell
16US Political Scene on Eve of Mexican War Even while Slidell was trying to negotiate, Polk was preparing for military actionIn June 1845, Brigadier General Zachary Taylor was ordered to prepare to move his army from Fort Jessup, Louisiana, into Texas.In July, Taylor began moving by land and water to Corpus ChristiFor the next seven months, Taylor trained his men at Corpus Christi
17US Political Scene on Eve of Mexican War With the diplomatic failure, Secretary of War William Marcy notified Taylor on January 13, 1846 to “advance and occupy, with the troops under your command, positions on or near the east bank of the Rio del Norte [the upper or New Mexico section of the Rio Grande]”
18US Political Scene on Eve of Mexican War The Mexicans and Americans stared at each other across the river for two weeksIn April, the Mexicans attacked an American scouting partyTaylor informed Washington, “Hostilities may now be considered as commenced.”Congress declared war on May 18, 1846
19US Political Scene on Eve of Mexican War Wilmot ProvisoIntroduced by Pennsylvania Congressman David Wilmot on August 6, 1846 to prohibit slavery in any territory gained from the war with MexicoApproved by the House but rejected by the SenateReintroduced in February 1847 with the same resultCartoon depicting the divisive effects of the Wilmot Proviso
20US Military on Eve of Mexican War Because of the soft support for the war, especially in the northeast, Polk decided to avoid large-scale use of the militiaAuthorized the raising of 50,000 volunteers, mostly from the southern statesAuthorized Regular Army to double its existing size to 15,000 by filling units up to full strengthPresident James Polk
21US Military on Eve of Mexican War America got most of its military ideas from EuropeAntoine-Henri de Jomini ( ) was a Swiss military theorist who sought to interpret NapoleonPublished the Summary of the Art of War in 1838Became the premier military- educational text of the mid- nineteenth century
22US Military on Eve of Mexican War As a product of the Enlightenment, Jomini sought natural laws to govern the conduct of warDeveloped a very geometrical and scientific approach to warStressed the principle of concentration, the decisive point, the strategic value of interior lines, and the close relationship between logistics and combatInterior lines are “those adopted by one or two armies to oppose several hostile bodies, and having such a direction that the general can concentrate the masses and maneuver with his whole force in a shorter period of time than it would require for the enemy to oppose them a greater force.”
23US Military on Eve of Mexican War The benefits of interior lines could be gained either by central position or superior lateral communicationsInteriorLinesExterior
24US Military on Eve of Mexican War In 1835, Winfield Scott’s three-volume Infantry Tactics was adopted by the ArmyEmphasized discipline over speed and mass over maneuverStressed close-ordered lines of either two or three ranks and discouraged the use of any movement faster than the quick time rate of 110 steps per minuteLoose order was allowed only in skirmishing tactics where advanced troops deployed forward of their main lines to cover their own troops and to develop the enemy’s fire.
25US Military on Eve of Mexican War Each regiment would have one company of rifles or light infantry to act as skirmishers for the entire regimentHowever, in Mexico, such skirmishers would be only deployed in small numbers as a reaction to terrain and circumstancesScott’s Infantry Tactics proved to be very appropriate for the situation in Mexico
26US Military on Eve of Mexican War Command and control was based largely on line-of-sight signaling, couriers, and audible signalsColor bearers were critical to command and controlThe commander’s physical presence on the battlefield was not just a sign of bravery but also his most reliable means of control
27US Military on Eve of Mexican War Prior to Mexico, the Army had not had to deploy and had not had to worry about long supply linesExpanded transportation distances and demands in Mexico would make it “the first steamboat war”
28US Military on Eve of Mexican War The most common firearm in Mexico was the flintlock musket with a range of 100 to 200 yardsThe percussion cap Model 1841 Springfield was the official standard shoulder arm, but traditionalists like Winfield Scott thought the system was too complicated and the flintlock prevailedLess traditionalist volunteer units like Jefferson Davis’s Mississippi Rifles were willing to use the new technology
29US Military on Eve of Mexican War The US had pursued a vigorous program to build its artilleryThe 1841 system featured bronze smoothbores usually organized into a six-piece battery of four guns and two howitzersThe six-pounder gun had an effective range of 1,523 yards
30US Military on Eve of Mexican War Following the example of the French and British, the US began organizing one company in each artillery regiment as light or “flying” artillery to be used with the infantryBecause artillery could fire canister at about 400 yards compared to the musket’s range of about 100 yards, the artillery had “stand-off”The artillery could blast holes in enemy defenses while remaining out of range of the infantryArtillery in Mexico was often used offensively in close coordination with an infantry assault
31US Military on Eve of Mexican War Mexico was the first time the US Army was organized into divisionsUnits pioneered by Napoleon to facilitate semi-autonomous flanking movementsThe Army had a shortage of senior leaders capable of commanding these larger, more flexible unitsThis deficiency was partly off-set by the small size of the units employed in Mexico and by the superior junior leadership
32US Military on Eve of Mexican War In 1817, Sylvanus Thayer replaced Captain Alden Partridge as superintendent of West Point and began reversing the damage Partridge had done.Thayer broadened and standardized the curriculum, established a system to measure class standing, organized classes around small sections, improved cadet discipline, created the office of commandant of cadets, and improved military training.“The Father of the Military Academy”
33US Military on Eve of Mexican War By the time of the Mexican War, Thayer’s reforms had produced a generation of men who would fill the junior officers’ ranks in Mexico.These lieutenants and captains stood in sharp contrast to the older officers who had not benefited from a systematic military education and training.The impact of Thayer and West Point was readily apparent in Mexico.West Point was founded in 1802 and was instrumental in training engineers in the 19th Century
34US Military on Eve of Mexican War Winfield Scott called his West Pointers his “little cabinet”Scott was unwavering in his acknowledgement of West Pointers declaring,“I give it as my fixed opinion that but for our graduated cadets the war between the United States and Mexico might, and probably would, have lasted some four or five years, with, in its first half, more defeats than victories falling to our share, whereas in two campaigns we conquered a great country and a peace without the loss of a single battle or skirmish.”
35Key PlayersJames Polk. President of the US. Staunch advocate of Manifest Destiny. Mexico is sometimes called “Mr. Polk’s War.”Thomas Hart Benton. Democratic Senator from Missouri. Considered for a lieutenant generalship by Polk to stave off the Whigs.Daniel Webster. Senator from Massachusetts. Example of Whig opposition to Mexican War.
36Key PlayersWinfield Scott. Thoroughly professional officer and hero of the war of Ordered by Polk to open a second front to rival Taylor.Stephen Kearney. Conducted a easy campaign to seize New Mexico and then pressed on to secure California.Zachary Taylor. Veteran of the War of 1812 and Indian Wars. Ordered by Polk to the Rio Grande. Polk saw him as a political rival.
37Key PlayersJohn Fremont. Was already in California on a mapping expedition. Helped secure the territory but refused to relinquish command to Kearney and was court martialed.John Sloat. Naval commander who helped Fremont secure California. Replaced by Stockton.Robert Stockton. Developed a naval blockade and assisted Kearney in the conquest of California.
38Key PlayersAlexander Doniphan. Led a regiment of Missouri volunteers. Helped Kearney secure New Mexico then entered north Mexico.John Slidell. Polk’s appointed minister to Mexico. Mexico failed to recognize Slidell as such and negotiations failed.Nicholas Trist. Ran afoul of both Polk and Scott but ultimately negotiated the treaty of Guadalupe Hidalgo.
39Key PlayersDavid Twiggs. Led main effort at Cerro Gordo. Scott felt Twiggs was “not competent to command an army in the presence of the enemy– nor its absence.”Gideon Pillow. Political general. Law partner of Polk. Exacerbated difficulties between Scott and Polk.John Wool. Division commander at Saltillo and Buena Vista. Maybe the best division commander but still unremarkable.
40Key PlayersWilliam Worth. Served first under Taylor, then joined Scott. Had some talent, but also a quarrelsome personality.Jefferson Davis. Commanded the Mississippi Rifles, winning fame at Buena Vista and showing the value of the rifle.Robert E. Lee. Member of Scott’s staff. Representative of the role played by engineers and West Pointers.