By 1780, the Revolutionary War was wrapping up with it being pretty obvious that most likely the British were not going to hold on to what they called the thirteen colonies. With victory pretty much guaranteed, the thirteen colonies, who now thought of themselves as the thirteen states, decided it was about damn time to set up a federal government in order to guarantee the British had no chance of ever coming back. What they ended up creating was a states’ rights advocate’s wet dream known as the Articles of Confederation, wherein each state regardless of size had one vote in Congress which had the power to do absolutely diddly-squat. It worked exactly as well as one might imagine, leaving the federal government broke pretty much immediately. Since the government having no money is kind of a problem, some of the more centralized thinkers of the day proposed an amendment wherein each state would be taxed according to the value of its real estate. However, this being the 18th century, a time when such calculations were a huge pain in the ass, the proponents of creating a federal tax soon shifted to the idea that the taxes should be based instead on the number of people in each state, a much easier calculation, or at least it seemed.
Certain things were easy to agree upon. For instance, all thirteen states agreed that Native Americans were totally not people so should not be counted. However, where they ran into a problem was how to count slaves. Now at the time, only three states had ended slavery; Massachusetts, New Hampshire, and Pennsylvania; but overall the southern states had a literal shit ton of slaves compared to the north, around a ratio of 7 to 1. As a result, the northern states were totally down with the idea of including slaves in the count of population for tax purposes, while the southern states pretty much said no fucking way. This led to Congress making one of the strangest compromises in history, wherein they decreed that each slave would only be counted as three-fifths of a person. So yeah, pretty fucked up. However, none of this mattered because enough states decided that the idea of a federal tax was stupid and so the amendment never passed.
The Articles of Confederation continued to be the law of the land over the next decade, during which time the number of states outlawing slavery rose to five with the addition of Connecticut and Rhode Island. Its probably worth mentioning that this didn’t mean that slaves were freed, just that any children born after the ban was put into effect wouldn’t be slaves. The idea was that slaves were property and you couldn’t just take people’s property away, even when said property were god damn human beings. Again, pretty fucked up. Anyways, eventually the whole mess that was the Articles of Confederation eventually was so close to collapsing that the states agreed that a new government was needed, resulting in it being replaced by the U.S. Constitution in 1789.
Now of course with the Constitution the whole idea of state population is rather important, what with it dictating how many votes each state gets in the House of Representatives and to elect the president. This of course re-ignited the whole debate on whether or not slaves should be counted. However, this time the opinions were reversed. In a rather ironic twist, the southern states, who pretty much thought of slaves as being the same as cattle, wanted the highest law in the land to declare slaves to be people. At the same time, the northern states, who were waking up to the fact that slaves were totally people, wanted the highest law in the land to view them as property. So yeah, seriously, super fucked up. Anyways, the debate over how to count slaves almost completely sank any chance of forming a new government, at least until the old three-fifths compromise was remembered, which was still just as exactly terrible as it was when it was first come up with a decade earlier.
As a result of the three-fifths compromise, the southern states got around a third more presidential electors and seats in the House of Representatives than they otherwise would’ve had. This allowed them to exert a much greater amount of control in the federal government, including putting in place pro-slavery Supreme Court Justices and ensuring that the number of slave states always remained close to the number of free states, which helped the shitty policy of slavery continue long after the majority of people in the country decided it was fucked up (70% of the non-slave population lived in the free states by 1860). This unbalance eventually culminated in the shit show known as the U.S. Civil War. Now one might wonder why the northern states agreed to such a shitty deal. Well first, they were quite literally afraid of the country ripping itself apart while still in its infancy, something that continually came close to happening over the next 70 years until it actually did happen with the aforementioned war between the states. Second, while the southern states did get more political power, they also had to agree to the same population counting method if the federal government ever imposed a national tax. This was favorable to the northern states, many of whom were hoping to see such a national tax enacted. Spoiler alert, it never was, mostly thanks to the increased political power of the southern states. So yeah, not the best moment in American history.