Let's admit the truth right away: Almost every Presidential election is predicted to be "groundbreaking" or "the most important in decades" or some other large adjectives.
This time, it's not an exaggeration to say that the presidential election of 2020 will change the course of history, but probably not for the reason you think.
Obviously if Trump gets defeated at the polls in November 2020 and is not re-elected, that would change the course of history.
But with less than a year until the next presidential inauguration, it will also change the course of history if Trump, who is literally hated by over 40% of adult Americans and only the third president in the history of the United States to be impeached, gets re-elected.
This is not a contradiction at all.
Here are the four biggest reasons why the 2020 presidential election will change the course of history:
1) The 2020 presidential election will have the highest voter turnout by far in many decades, significantly higher than any presidential election in the last 20 years, and probably the last 50 years.
2) African American support for the democrats will be the lowest in over 50 years. Have you heard of Candace Owens?
3) Trump will be re-elected by winning a majority of electoral votes in the electoral college, while again for a second time receiving less popular votes than whichever democrat goes up against him.
4) And most importantly for changing the course of history, that will lead to the biggest push yet so far, which will eventually succeed, at finally abolishing the electoral college.
Over time the abolishing of the electoral college will likely be negative for the republican party, possibly as soon as the first American presidential election that will be decided solely by the popular vote.