The slave power of the South began at the Constitutional Convention in 1787. At the time, the Constitution was acceptable to the southern states only if the north accepted the "3\5ths rule". This rule demanded that 3/5ths of the slaves be counted as part of the American census even though these slaves had no voting rights. In other words, if a state contained 100,000 slaves, it would add 60,000 people to the state's population figure. The total figure would determine the number of state representatives. Since over 90% of the slaves were in the south, this added to the congressional power of representation in the newly formed Congressional body of the House of Representatives and associated committees. Southern states became weighted just as heavily as northern states even though there was substantially less of a voting public.

This was a fairly hot issue at the time. Since southerners saw slaves as property, the north would ask sarcastically, "Why can't we count our cows as people since they too are property?" The only person to accurately forecast what this would mean with regards to state representation in the future was a man by the name of Governeur Morris who saw more clearly than others that southern slave power would eventually signify unequal representation. Most men at the convention suspected that slavery would eventually die out (the cotton super-economy had not been invented yet) and that the numbers would eventually stabilize. Therefore, the compromise was made and the Constitution passed contingent on this 3\5ths rule.

The 3/5ths rule quickly grew in favor of the slave states almost exponentially. After 1787, slaves were imported at dramatically higher rates than before adding even more representatives to southern states. In 1819 the slave population was 1,191,364 according to the last census. Because of that population, the 3/5ths rule allowed for at least 20 more representatives and 20 presidential electors added to the political power of the southern states. Most of the patronage doled out to those seeking political appointments, needless to say, went to slaveholders. Southerners held 51% of the top government posts under John Adams, 56% under Jefferson, and 57% under Jackson even though the South's population was barely half of what the North's was during that period. President John Tyler nominated slaveholding firebrand and slave protectionist John Calhoun as Secretary of State in 1844 and the Senate didn't even bother to hold a hearing on the appointment. *

According to historian Leonard Richards... "in the sixty-two years between Washington's election and the Compromise of 1850, for example, slaveholders controlled the presidency for fifty years, the Speaker's chair for forty-one years, and the Chairmanship of the House Ways and Means for forty-two years. The only men re-elected president - Washington, Jefferson, Madison, Monroe, and Jackson - were all slaveholders. The men who sat in the Speaker's chair the longest - Henry Clay, Andrew Stevenson, and Nathaniel Macon - were slaveholders. Eighteen of thirty-one Supreme Court justices were slaveholders." ¹

Accusations from the North of southern slave power was evident in Congress from as far back as the Louisiana Purchase. However, the idea of slave power (and the political resentment) made strong appearances during the Missouri Compromise of 1819-1820, the Gag Rule of slavery petitions aimed at John Quincy Adams from 1835-1844 and discussions on the annexation of Texas throughout the late1840s. By the 1850s, discussions of slavery and political slave power were constant battles within Congress and made headlines every year until the eve of the Civil War.

As the Whig party came to have some minority representative power in the early 19th century, it was fairly clear they would be the party most supportive of anti-slave legislation. However, southern Whigs frequently voted with southern Democrats while northern Whigs could not get the same support from northern Democrats, making the Democrats the strongest and most consistent voting bloc by far (and having a stronger pro-slavery influence) throughout the 1820, 30s, and 40's.

Why did northern Democrats side with their southern counterparts instead of along north-south slave lines? As Leonard Richards puts it, "The subordinate position of northern Democrats undoubtedly influenced their behavior. All those with national aspirations knew they had an advantage over their Whig rivals in being members of the nation's dominant party. But they also knew that they had to pay more heed to their southern colleagues to have any chance of being nominated for the presidency or Speaker of the House or chair of the House, Ways and Means. Some, like Franklin Pierce and James Buchanan, accepted this reality and catered to their southern colleagues for their entire political careers. Others like Martin Van Buren and Stephen A. Douglas, spent the better part of their political lives catering to the South but eventually found southern demands intolerable." ¹

Historian Garry Wills has postulated that without the additional "slave" votes, Jefferson would have lost the election of 1800 (Adams won a majority of the popular vote and only the skewed Electoral College gave Jefferson the Presidency). Also, "...slavery would have been excluded from Missouri...Jackson's Indian removal policy would have failed...the Wilmot Proviso would have banned slavery in territories won from Mexico....the Kansas-Nebraska bill would have failed...." ²

Throughout the 1840s, however, the Democratic Party base in the north slowly began having second thoughts about always voting with their Democratic counter-parts on the South. By 1854, the northern democrats were losing representative seats in Congress, and by 1856 the new Republican Party - with a solidly anti-slavery platform - had emerged as a potential frontrunner.

¹ Leonard Richards, The Slave Power: The Free North and Southern Domination 1780-1860, 2000
² Wikipedia reference: Wills,Garry. "Negro President": Jefferson and the Slave Power. Houghton Mifflin, 2003