The Reconstruction Amendments (13th, 14th, and 15th Amendments to the Constitution) represented a fundamental shift in the balance of power between the states and the federal government, even though their full effect took a century to fully emerge.
Before the Civil War, the states and the federal government were locked in an uneasy balance of power. The federal constitution listed certain areas (treaties, post offices, patents, interstate commerce, constitutional interpretation, and more) where federal supremacy was clear (via Article VI, Clause 2), but other areas defaulted to the states (made explicit by the 10th Amendment).
Southern planters generally favored state government power, as they were afraid that the foundation of their raw-material economy would be undermined if the federal government — especially a federal government led by Northern manufacturing interests — gained the power to abolish slavery in the South. Their interests were directly represented in the Constitution itself in several places: Article 1, Section 9 forbid banning the slave trade until at least 1808, the “Enumeration Clause” counted slaves as 3/5ths of a person for the purposes of the census (though they could not vote, of course), and the “Fugitive Slave Clause” required escaped slaves to be returned ”on Claim of the Party.”
Despite these protections, Southern slaveholders grew increasingly nervous that their economic system — which they increasingly argued was not just a “necessary evil,” but rather constituted a “positive good” — would either be directly challenged by the North, or would die out if it could not expand westward.
In the face of growing Northern power, arguments for state’s rights grew in the South — after all, if state government was at least equal to the federal government in power, then it would be difficult for the federal government (even if eventually dominated by the North) to restrict or eliminate slavery.
But despite these growing states’ rights arguments — including Georgia and President Andrew Jackson’s refusal to follow the Supreme Court ruling that federal treaties trumped state action in the Cherokee cases — Southerns appeared to embrace a different view of the balance between federal and state power in 1850.
Before 1850, Northern states had become increasingly reluctant to return runaway slaves to the South, denying planters their property without recompense. Laws to add more legal protections before alleged escapees would be returned meant that the burden on Southerns seeking the return of their property grew. One reaction was vigilante-style kidnapping of blacks in the North, some of whom turned out to be free blacks, not escaped slaves. Northern laws punished kidnappers, and Southerners were unhappy.
The Fugitive Slave Act of 1850 was designed to allay the anger of the South. It created a new federal agency and new federal commissioners who acted much as had U.S. Marshalls previously. These new commissioners could deputize and track escaped slaves, and were paid by the federal government and also for each slave returned. Soon, this new agency became the largest federal employer, exceeding the number of postal employees soon after it was passed.
The Fugitive Slave Act was anything but pro-state’s rights. To assist commissioners in apprehending slaves, troops were even sent into Boston to quell dissent and escort a captured slave from the city. Northern state laws on due process were ignored, and alleged escapees received no jury trial, no were they able to testify on their own behalf — despite Northern laws. In other words, the South embraced the law and the exercise of federal power.
But this new balance only postponed the battle between North and South for eleven more years. Western states were increasingly adopting anti-slavery positions (although they also sometimes banned African-Americans from moving there), and the South felt increasing pressure. Even the 1857 Dred Scott decision by the Supreme Court, led by the Southern Chief Justice Roger B. Taney, and intended to settle the slave question “once and for all” only delayed the Civil War by another few years.
By 1861, with the election of Abraham Lincoln on a platform that opposed the expansion of slavery westward (though not the abolition of slavery in the South — that came later, during the war), the South had decided that secession was the only option to protect their economic and political system.