In 2021 DonaldTrump refused to accept the results of the election he lost. And millions of his supporters believe the election was fraudulent.
They attacked and invaded the Capitol in Washington to prevent JoeBiden being officially confirmed president. Five people were killed in the fighting. Members of congress were threatened with kidnapping and potentially death.
In other words, this is the closest the UnitedStates has got to the fall of its democracy in its history.