Bringing Up Drugs? Undermining the Debate? These Are Old Trump Tactics.

To spend time on former President Donald J. Trump’s corner of social media is to witness any number of contradictory, unproven or outright conspiratorial ideas blooming, all at once. The approaching presidential debate has apparently sent him into overdrive.

On social media and at rallies, Mr. Trump has suggested that President Biden is taking performance-enhancing drugs ahead of the debate. Then, on Monday, he called on Mr. Biden to take a drug test. Mr. Trump banged out the demand on his social media account: “DRUG TEST FOR CROOKED JOE BIDEN??? I WOULD, ALSO, IMMEDIATELY AGREE TO ONE!!!”

This was a dramatic turnaround for Mr. Trump, who just days ago was also suggesting that Mr. Biden would be spending most of his debate preparations sleeping. Earlier this year, he called Mr. Biden “the WORST debater I have ever faced. He can’t put two sentences together!”

But in recent days, he has called Mr. Biden a “worthy debater,” reminding his audience of Mr. Biden’s performance in vice-presidential debates against Paul Ryan in 2012. It all amounts to an apparent last-ditch attempt to reset the low expectations he had established for the 81-year-old president early on. The Trump campaign has also attacked the debate moderators, two veteran CNN journalists, by accusing them of biased coverage of Mr. Trump in the past.

Mr. Biden’s advisers see these outbursts as an attempt by the former president and his campaign to fling some red meat at his base and move the goal posts ahead of a high-stakes event. For Mr. Trump, this is not an uncommon tactic: He accused Mr. Biden of taking performance-enhancing drugs in 2020, and suggested Hillary Clinton was taking drugs ahead of a debate in 2016. In all of those cases, Mr. Trump also falsely claimed that the election itself was rigged.

“Donald Trump is so scared of being held accountable for his toxic agenda of attacking reproductive freedom and cutting Social Security that he and his allies are resorting to desperate, obviously false lies,” Lauren Hitt, a spokeswoman for Mr. Biden’s campaign, said in a statement.

Mr. Biden has been preparing for the better part of a week at Camp David. Mr. Trump has said he’d rather hone his debate message in front of supporters at his rallies.

The Biden campaign proposed holding a debate early enough in the election season to give voters a clear view of both candidates. It wanted to strip down the audience to limit applause and jeers, and wanted two debates, one in June and another in September. Drug testing was never a requirement. Both candidates agreed to the terms.

When asked why Mr. Trump would agree to a debate if he had longstanding concerns, Karoline Leavitt, a spokeswoman for the Trump campaign, said that the former president was keeping a promise to Americans.

“President Trump delivers on his promises, and he promised the American people he would debate Joe Biden, anytime, anywhere, any place,” Ms. Leavitt said.

And despite Mr. Trump’s repeated attacks and attempts to undermine the debate, Ms. Leavitt said that he would still attend the matchup, even if drug tests were not performed.

“President Trump will be on the debate stage on Thursday,” she said.