In a Twitter message posted on Sunday, President Donald Trump called for himself and Democrat Joe Biden to submit to drug tests before or after the first presidential debate, which will take place on Tuesday.
"I will be strongly demanding a Drug Test of Sleepy Joe Biden prior to, or after, the Debate on Tuesday night," Trump wrote.
"Naturally, I will agree to take one also," he confirmed, suggesting that only mind-enhancing substances could have caused the alleged fluctuations in the strength of Biden's performances at the Democratic Party primary debates earlier this year.
"His Debate performances have been record setting UNEVEN, to put it mildly. Only drugs could have caused this discrepancy???"Trump has long claimed that the Democratic presidential nominee is being drugged before important public events.
During a campaign rally last week, Trump said that Biden receives a "big fat shot in the a**" before appearing in public and stressed that tests are necessary.
"We're going to ask for a drug test. Both of us, I'll take it, he'll take it," he said.
Trump has not offered concrete evidence for his claims, but he has repeatedly pointed to Biden's performance in primary debates.
In an August interview, he said that the former Delaware senator "wasn't even coherent" in the debates when there were multiple candidates on stage, but excelled during his one-on-one clash with Vermont Sen. Bernie Sanders.
Biden recently dismissed Trump's claims, describing them as "foolish."
In an interview on Saturday, Biden suggested that he is looking forward to debating Trump, but noted that he expects vicious personal attacks.
He also said that the commander-in-chief is "not that smart" or familiar with the policy-making process.
"He doesn't know much about foreign policy, he doesn't know much about domestic policy, he doesn't know much about the detail," he stated.
In contrast, Trump has been managing expectations for himself, repeatedly describing his opponent as an experienced and skilled debater. He also complained about Fox News anchor Chris Wallace -- who will moderate the Tuesday event -- and the media more broadly, noting that he expects the press to praise the Democrat regardless of how well he performs.
The Biden campaign reportedly expects Trump to focus on attacking Biden on a personal level while slamming him for supposedly catering to the progressive wing of the Democratic Party.
Some in the Trump camp reportedly fear that the commander-in-chief and his allies have lowered the bar for his opponent by repeatedly alleging that he is suffering from dementia.