The Mexican-American War illustrates how important slavery was for the expansion of the United States.
Unless you are Mexican, it is easy to forget that California was not always in the United States, having been a part of Mexico until the Mexican-American War of 1846-48, after which it was annexed. Slavery had much to do with the origins of that war, since white settlers hoping to grow cotton on slave plantations had fought for the secession of Texas in 1836, and then supported its annexation by the United States in 1845; a disagreement over Texas’ western boundary would lead to war with Mexico the following year. My argument here, however, is that slavery was also crucial to the outcome of the Mexican-American war because the goods produced by slaves were essential to the United States’ healthy public finances, which allowed it to defeat its poorer neighbour. This blog post thus makes a small contribution to the ongoing debate about slavery’s role in the development of the United States in the long nineteenth century.1