By the time of the Constitutional Convention in 1787, a division between slave and free states had begun to emerge. Massachusetts, New Hampshire, and Vermont (which would become the fourteenth state) had abolished slavery, while Pennsylvania, Connecticut, and Rhode Island were in the process of doing so. Southerners at the convention feared that in the new nation, their slaves would escape to these free states and be forever lost. Thus, late in the convention, Pierce Butler of South Carolina proposed that the fugitives from justice clause, designed to facilitate the return of accused criminals, also provide for the return of fugitive slaves. The convention rejected this idea but a few days later adopted, without debate or vote, a separate provision for the return of fugitive slaves. The clause provided that "No Person held to Service or Labour in one State, under the Laws thereof, escaping into another, shall, in Consequence of any Law or Regulation therein, be discharged from such Service or Labour, but shall be delivered up on Claim of the Party to whom such Service or Labour may be due."
During the ratification debates, southern supporters of the Constitution used the clause to bolster their support for the document. At the South Carolina ratifying convention, for example, Charles Cotesworth Pinckney, who had been a delegate at the Philadelphia convention, declared, "We have obtained a right to recover our slaves in whatever part of America they may take refuge, which is a right we had not before." Similarly, in Virginia, Governor Edmund Randolph and James Madison, who had also been delegates in Philadelphia, used the fugitive slave clause to show that the Constitution protected slavery.
The fugitive slave clause was placed in Article IV of the Constitution, immediately after the clause providing for the return of fugitives from justice. But the two clauses, although juxtaposed, differed significantly. The fugitives from justice clause was predicated on legal due process. It provided for the return of a fugitive who was "charged in any State with Treason, Felony, or other Crime." The term "charged" implied some sort of legal proceeding—such as a grand jury indictment—that established prima facie guilt. The fugitives from justice clause also provided a mechanism for returning alleged criminals. The clause said that "on Demand of the executive Authority of the State from which he fled," the fugitive from justice was to be "delivered up, to be removed to the State having Jurisdiction of the Crime." In other words, after an indictment the governor of the state would contact the authorities where the fugitive was hiding and request that the fugitive be arrested. The governor would then send someone to receive the prisoner and bring him back for trial.
The fugitive slave clause, on the other hand, provided no clear mechanism for the return of a fugitive slave. The clause declared the fugitive would be returned "on Claim of the Party to whom such Service or Labour may be due." Such language implied that the fugitive slave would normally be in the custody of someone, or even be working for someone as a slave. The fugitive was to be "delivered up on Claim" of the owner. But the clause did not indicate how that delivery was to take place, who was to pay for it, or what would be needed to prove that the "Claim" was legitimate.
Perhaps the most significant difference between the two clauses was their lack of symmetry. Each state had two strong interests in cooperating in the seizure and arrest of fugitives from justice. No state would want a criminal hiding within its boundaries. That alone was incentive enough to help return fugitives. In addition, however, all states would eventually seek the return of a fugitive from justice, and thus there was a strong incentive for mutual cooperation. This did not exist with fugitive slaves. The northern states had no strong need to prevent blacks from escaping into their jurisdiction. Indeed, such fugitive slaves were likely to be highly motivated people who were determined to be successful in a free society. Nor could the free states expect any symmetry in this process. They would never seek to recover fugitive slaves because they did not have slavery.
In 1791 Pennsylvania sought the return from Virginia of three fugitives from justice who were accused of kidnapping a free black named John Davis and taking him to Virginia, where he was enslaved. The governor of Virginia refused to cooperate in the extradition of the three men, arguing that in fact Davis was a fugitive slave from Virginia, and that even if he was not, kidnapping a free black was not considered a felony in Virginia. The governor of Pennsylvania went directly to President George Washington for help. Congress responded in 1793 with a law that regulated both the extradition of criminals and fugitive slaves.
Although it covered both issues, the act was known as the Fugitive Slave Law of 1793. The law required that persons seeking runaway slaves obtain a certificate of removal from any federal judge or any state judge, magistrate, justice of the peace, or other judicial official. In order to receive the certificate, the claimant had to provide an affidavit, sworn before a judge in his home state, describing the alleged slave. The law provided a five-hundred-dollar penalty for anyone interfering with the return of a fugitive slave and also allowed a master to sue anyone who successfully helped his slave escape for the value of that slave. The law did not provide a criminal penalty for helping a slave escape. While many northerners did help fugitive slaves, before 1830 there were no known suits against them.
This procedure created a great danger for the growing free black population of the North. Because of abolition in upper New England and private manumission and gradual emancipation statutes in the rest of the North, by 1790, 40 percent of the blacks in the region were free. By 1800, 56 percent were free, rising to 83 percent by 1820. In 1830 there were over 125,000 free blacks in the Northeast but fewer than 3,000 slaves. Throughout the North, blacks and whites alike worried that southerners might fraudulently claim free blacks as their fugitive slaves, or that they might simply try to kidnap free blacks and take them to the South, where they could be sold. By 1829 a number of northern states, including New York, New Jersey, and Pennsylvania, had passed personal liberty laws, which supplemented the 1793 law by demanding greater proof before a black could be removed from a state as a fugitive slave. These laws typically required that claimants bring an alleged fugitive slave before a state magistrate or judge, who could consider the evidence before allowing a person to be removed as a slave. No known cases under the 1793 law reached the federal courts before 1830. There are few reported cases in which courts in the free states supported the claims of masters seeking to recapture their runaways, but by and large before 1830 the act of 1793 produced few cases and did little to help slave owners recover their runaway slaves. However, in the period from 1793 to 1829 there were scattered instances of free blacks, especially children, being kidnapped and taken south. While few in numbers, these kidnappings worried northern blacks, especially those who lived along the Ohio River, in port cities like New York and Philadelphia, or in southern Pennsylvania. Kidnappings were illegal and were not sanctioned by the Fugitive Slave Law, but free blacks saw little difference between the agent of the master armed with a certificate of removal and the kidnapper. Both intended to reduce African Americans to bondage.