True Democracy is a bad thing for the people. Here's why...
In a Democracy, 51% win over the 49% in their voting. This makes slaves of the 49%... slaves to the desires of the 51%.
In a large country, 51% of the people can't all govern the country directly. So, a handful of people are elected by the 51% to do the governing for them.
Then the handful of governing people do whatever they want, and the country becomes a dictatorship by a small group.
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The above is why the people who set up the American government made two parts to it. The formal government is a Democracy, but any part of it can be nullified by the 12-person jury in any individual case. If enough various juries nullify a part or law, it will ultimately be repealed for everyone.
Doing it this way makes the government a true government of all the people, while at the same time having the benefits of a formal government to keep order.
The problem with the US is that the people don't understand this very much. So, they don't use what they don't understand... except a little.
Btw, the American Democracy is inside of and a part of the American Republic, simply because of the above.