In the early 1820’s, Americans were invited by the Mexican government, which was pushing for development, to settle and farm on the borderland of Texas. After more and more Americans settled (around 20,000 Americans and 4,000 slaves), a push for independence from Mexico ensued. After a short war between the settlers and Mexico, President Jackson recognized Texas’ independence which thus became known as the Republic of Texas (sound familiar?).

The Mexican government refused to acknowledge the independence of Texas, and turned down a United States offer to buy the territory, as well as lands in California and the southwest. Most in Texas and in the U.S. wanted to admit the territory in as a new state. So, General Zachary Taylor led his troops to the southern border of Texas, the Rio Grande River. The Mexicans, however, believed the border to be to the north of the Rio Grande, and that Taylor had crossed into Mexican territory, thus carrying out an act of aggression. After a border incident where an American was killed, President James Polk was able to convince Congress to declare war. The Mexican War of 1846 was the result.

The War was rather short, and the heavily outnumbered, but better organized, American troops were able to defeat Mexico, but at a heavy cost. 104,556 Americans served in the Mexican War, and 13,768 were killed; the highest death rate of any American war up to that time.

What does the Mexican War which occurred in 1846 have to do with the Civil War which started in 1861? After America defeated the Mexicans, we not only acquired the Texas territory, but also the California and New Mexico territories (Nevada, Utah, Arizona, New Mexico, and parts of Oklahoma, Colorado, and Wyoming). Now the question of whether or not these territories would allow slavery came to the surface. Northerners were basically against fighting the War for the cause of slavery expansion (simply because it was not a cause that directly involved them), and thus they were against any results of the War that would indicate such a cause. However, since most of these new territories were south of the Missouri Compromise line, Southerners argued they had the right to expand slavery to those new territories.

In August of 1847 Congressman David Wilmot of Pennsylvania attached a proviso to an amendment that would exclude slavery from the newly acquired territories. Although the House voted for it twice, the Senate defeated the measure. Wilmot’s proviso, although unsuccessful, brought the heated issue of slavery expansion that the Missouri Compromise seemed to fix back to the center of political debate.

Source Used: Don’t Know Much About The Civil War, Kenneth Davis, 1996.

Next Article: The Compromise of 1850 and the Fugitive Slave Law.