Slave owners lived in constant fear of slave revolts, and justly so. The average holding varied between four and six slaves, and at the peak of slavery in the US slaves occupied more than 20% of the population. If slaves were to get fed up with their horrible situation they might be able to overpower their masters and begin freeing slaves from other plantations. These fears were further amplified by the Hattian Rebellion in 1791 in which the local slaves brutally killed 75,000 French citizens, gaining their freedom in the process. Many in the United States feared that a similar situation would unfold if their slaves rebelled en masse.
The Founding Fathers, the framers of the Constitution, wanted to form a government that did not allow one person to have too much authority or control. While under the rule of the British king they learned that this could be a bad system.
A two-thirds majority vote in both the House of Representatives and in the Senate is required to override a presidential veto. The exact number depends on how many representatives vote; therefore, the actual number is subject to chance
