whether economic differences between the mainly industrial North and the mainly agricultural South helped cause the war. Most historians now disagree with the economic determinism of historian Charles A. Beard in the 1920s, and emphasize that Northern and Southern economies were largely complementary. While socially different, the sections economically benefited each other. Protectionism Owners of slaves preferred low-cost manual labor with no mechanization. Northern manufacturing interests supported tariffs and protectionism while Southern planters demanded free trade. The Democrats in Congress, controlled by Southerners, wrote the tariff laws in the 1830s, 1840s, and 1850s, and kept reducing rates so that the 1857 rates were the lowest since 1816. The Republicans called for an increase in tariffs in the 1860 election. The increases were only enacted in 1861 after Southerners resigned their seats in Congress. The tariff issue was a Northern grievance. However, neo-Confederate writers have claimed it as a Southern grievance. In 1860–61 none of the groups that proposed compromises to head off secession raised the tariff issue. Pamphleteers from the North and the South rarely mentioned the tariff. Nationalism and honor Nationalism was a powerful force in the early 19th century, with famous spokesmen such as Andrew Jackson and Daniel Webster. While practically all Northerners supported the Union, Southerners were split between those loyal to the entirety of the United States (called "Southern Unionists") and those loyal primarily to the Southern region and then the Confederacy. Perceived insults to Southern collective honor included the enormous popularity of Uncle Tom's Cabin and abolitionist John Brown's attempt to incite a slave rebellion in 1859. While the South moved towards a Southern nationalism, leaders in the North were also becoming more nationally minded, and they rejected any notion of splitting the Union. The Republican national electoral platform of 1860 warned that Republicans regarded disunion as treason and would not tolerate it. The South ignored the warnings; Southerners did not realize how ardently the North would fight to hold the Union together. Lincoln's election The election of Abraham Lincoln in November 1860 was the final trigger for secession. Southern leaders feared that Lincoln would stop the expansion of slavery and put it on a course toward extinction. However, Lincoln would not be inaugurated until five months after the election, which gave the South time to secede and prepare for war in the winter and spring of 1861. According to Lincoln, the American people had