Among the numerous steps preceding the Emancipation Declaration, the 1807 federal law abolishing the importation of enslaved people and the 1820 Missouri Compromise that limited slavery in newly admitted states were significant milestones.

In 1807, the US Congress passed a law making it a federal crime to import enslaved people into the country. The law became effective January 1 of the following year. The US action followed the 1807 enactment of a similar law in Great Britain. The US law also expanded on a 1794 law that had made it illegal for American ships to participate in the international slave trade. The new law both identified specific aspects of the trade that were criminal and created specific penalties for each element. The passage of this comprehensive law indicated shifting opinion against slavery. However, it did not offer federal protection to Africans who were illegally imported. Their legal fates were left in the hands of the individual states.

The Missouri Compromise of 1820 was an agreement in the U. S. Congress regarding the number and location of states in the Union in which slavery would be legal or illegal. Its name is associated with the process of Missouri becoming a state. In applying for admission as a state, the territorial government and statehood sponsors wanted to allow slavery. Because many Americans opposed this, the compromise reached also allowed Maine’s admission as a state in which slavery was legally prohibited. Furthermore, in every future state north of 36º 30´ latitude within the Louisiana Territory, slavery would be illegal. This event is important because it represented the ongoing efforts at equilibrium between pro-slavery forces and abolitionists. It postponed a decision about implementing a national prohibition of slavery.