WASHINGTON (Reuters) -Former President Joe Biden's son, Hunter Biden, said his father's disastrous debate performance against President Donald Trump that led to the Democrat stepping aside as presidential candidate was the result of him taking Ambien due to his travel. Joe Biden's office did not immediately respond to a request for comment late on Monday. The former president's debate performance against then-Republican presidential candidate Trump, in which the Democrat regularly struggled to finish his thoughts, triggered a backlash against Biden's candidacy for the 2024 elections.