Just a matter of passing interest.
In the era between WW2 and Trump, only two elected presidents have run for a second term and lost the general election:
In 1980, Jimmy Carter ran for a second term. Forty-four million Americans went to the polls to vote for his main oppponent (Reagan). In all, 51 million Americans voted against him.
In 1992, George Bush the Elder tried for a second term. Forty-five million Americans went to the polls to vote for his main oppponent (Clinton). In all, 65 million Americans voted against him.
In 2020, Donald Trump the Elder ran for a second term. Eighty million Americans went to the polls to vote for his main oppponent (Biden). In all, 83 million Americans voted against him.
The comparison is made more significant by the fact that Americans were not universally and specifically rejecting Carter and Bush, two decent men. Many Americans liked those two but nonetheless turned out to vote for charismatic opponents in elections complicated by substantial third-party voting. In the 2020 election … well, nobody thinks of Biden as Joey Charisma. Furthermore, down-ballot Republicans did fairly well. It’s obvious that the vast majority of those eighty million people who voted against Trump were casting votes specifically to reject Donald Trump.
It was the most resounding rejection of a president in modern history, and by a very large margin. Before this, no modern President trying to be re-elected for a second term had ever been replaced by an opponent receiving more than 45 million votes. Trump has been replaced by an opponent receiving 80 million votes.
In fairness, we should also note that no President running for re-election ever received as many votes as Donald Trump.
Voter turnout in the 2020 Presidential election was the highest it has been in 120 years! There were record numbers of votes for the president, and even more impressive record numbers of votes against him. Because Donald Trump is so loved and so hated, he has in a sense re-energized American democracy as much as he has polarized it. His very presence has made people on both sides more aware of the importance of the right to vote, and of the potential cost of not exercising that right. He has raised the stakes.