History short term and long term are affected by events that no one can predict.
There are so many “What Ifs” just in the past generation since 2000!
For example, if Al Gore had won the 2000 Presidential Election, it is debatable whether the September 11 attacks would have succeeded, and whether America would have gone to war in Afghanistan and Iraq, both engagements not fully ended, and causing the loss together of more than 7,000 American soldiers.
If the Democrats had been able to keep control of both houses of Congress in the last six years of the Barack Obama Presidency, so much more could have been accomplished in legislation, instead of by executive orders by President Barack Obama, and Obama might have been able to be as significant as Franklin D. Roosevelt and Lyndon B. Johnson, who had massive margins in both houses of Congress throughout their time in office.
If Joe Biden had not lost his son, Beau Biden, in 2015, it is thought possible that he might have defeated Hillary Clinton for the Democratic Presidential nomination in 2016, and might have defeated Donald Trump, saving America from the literal nightmare of the Trump Presidency in so many ways.
Finally, despite all of the horrors of the Trump Presidency, if it had not been for the COVID 19 Pandemic and the incompetent and uncaring handling of that crisis, it is possible to believe that Trump might have won reelection, and that would make the one term nightmare so many times worse!