The mid-nineteenth century witnessed two major wars on U.S. soil: the Mexican-American War and the Civil War. That Abraham Lincoln would commit the country to civil war appears to require little explanation, since he endorsed the abolition of slavery and the preservation of the young nation. However, Lincoln's disdain for the Mexican-American War, which was ostensibly fought to keep Texas in the Union, requires some examination. After all. Lincoln's swift military response to the Southern secessionists at the beginning of the Civil War illustrates that Lincoln would not shrink from battle if the war could ensure a united country. Perhaps Lincoln's resistance to the Mexican-American War can best be seen in light of his sincere belief that President Polk had overstepped his constitutional boundaries in declaring war against Mexico, a sovereign nation. In this light, it is perhaps ironic that Lincoln's own presidential legacy includes a greater centralization of federal government power.