No one wanted the president or anyone to abuse the power they were given so James Maddison came up with checks and balances so that every branch would balance each other. Ex: the legislative branch can pass a law. The way the executive branch checks that is by either agreeing with it or vetoing it. Second, the judicial branch apprehends the laws.
The system of checks and balances ensures that no single branch of government (legislative, judicial, executive) can dominate over the other two. ... For example, the legislative branch makes laws, the executive branch approves these laws, and the judicial branch has the power to veto these laws.
To answer the first question, slaves in African communities were held as equals and in American communities they are treated as an object no a person. (I hope that helped)