This is a very interesting question because it can include so many different disciplines such as philosophy, history, and writing.
If we study history, we can find patterns which when repeated seem to invariably lead to similar or even the same results. For example, history shows us that each and every time that a government over spends with money which it does not have, the inevitable result is inflation. The most recent example is the American government overspending from 2020 to 2023, causing the inflation which is only now receding but is still affecting the lives of millions of Americans.
The writers of the American Constitution were very aware of and worried about the fact that historically democracies usually devolved into mob rule and from there into a tyranny. This usually began during times of scarcity where a strong man would develop a large following by promising if he were in power, he would provide them the necessities which they lacked. Therefore, the Founders were very concerned about this danger in a democratic society and strove to develop a governmental system which would minimize the chance of it happening here. That is why we have our three different branches of government, each one with powers balancing the others and including a Supreme Court upon which the justices serve for life and so hopefully won't be persuaded by political interests. It is why the Electoral College became a part of the Constitution, as the last barrier to mob rule.
The Founders were also concerned about another danger of democracy, which they called "the tyranny of the majority." Benjamin Franklin is supposed to have expressed it by saying that a democracy is two wolves and one sheep voting on what to have for dinner. That is why our Bill of Rights is so important, as it is a major bulwark protecting the rights of each individual, even when those rights conflict with a majority opinion.
Therefore, by studying the past we are enabled to foresee future possibilities. By doing so we hope to build on what was good and right in history, and protect against repeating what was evil.