Under indictment and enraged, former President Donald J. Trump — with the help of Republican allies, social media supporters and Fox News — is lashing out at his successor in the hopes of undermining the charges against him.
“A corrupt sitting president!” Mr. Trump blared on Tuesday night after being arrested and pleading not guilty in Miami. “The Biden administration has turned us into a banana republic,” one of his longtime advisers wrote in a fund-raising email. “Wannabe dictator,” read a chyron on Fox News, accusing Mr. Biden of having his political rival arrested.
The accusations against Mr. Biden are being presented without any evidence that they are true, and Mr. Trump’s claims of an unfair prosecution came even after Attorney General Merrick B. Garland appointed a special counsel specifically to insulate the inquiries from political considerations.
But that hardly seems to be the point for Mr. Trump and his allies as they make a concerted effort to smear Mr. Biden and erode confidence in the legal system. Just hours after his arraignment, Mr. Trump promised payback if he wins the White House in 2024.
“I will appoint a real special prosecutor to go after the most corrupt president in the history of the United States of America, Joe Biden, and the entire Biden crime family,” Mr. Trump said during remarks at his golf club in Bedminster, N.J.
On Twitter, the former president’s followers used words like “traitor,” “disgrace,” “corrupt” and “biggest liar” to describe the current president. And while Fox News said on Wednesday that the “wannabe dictator” headline was “taken down immediately” and addressed, the network counts Mr. Trump’s many followers as loyal viewers.
The response from Mr. Biden and his advisers has been studious silence.
The president has vowed not to give the slightest hint that he is interfering in the criminal case against Mr. Trump, and he has ordered his White House aides and campaign staff members not to comment. That decision has quieted what is usually a robust rapid response team that aims to counter Republican attacks.
The president’s press aides responsible for instantly blasting out pro-Biden commentary to reporters have gone dark. Even Senator Chuck Schumer, the majority leader, issued a terse “no comment” on Wednesday.
Jill Biden, the first lady, broke the code of silence on Monday, telling donors at a fund-raiser in New York that she was shocked that Republicans were not bothered by Mr. Trump’s indictment. “My heart feels so broken by a lot of the headlines that we see on the news,” she said at the event, according to The Associated Press.
The attorney general also weighed in — somewhat — on Wednesday with his first public comments since Mr. Trump was charged. He took the opportunity to defend Jack Smith, the special counsel, as “a veteran career prosecutor.”
“He has assembled a group of experienced and talented prosecutors and agents who share his commitment to integrity and the rule of law,” Mr. Garland said.
Still, the no-comment strategy out of the White House is reminiscent of the determined silence by Robert S. Mueller III, the special counsel who investigated Russian interference in the 2016 election and links between Russian operatives and Mr. Trump’s campaign. Mr. Mueller said virtually nothing for more than a year as Mr. Trump and his allies attacked his investigation and his motives.
Like Mr. Mueller’s approach, Mr. Biden’s refusal to comment is intended to make sure he does not provide ammunition that his adversaries can try to use to undermine his credibility and integrity.
But in the end, the sustained assault on Mr. Mueller and his investigation helped Mr. Trump create a false narrative and survive the damning revelations contained in the more than 400-page report bearing the prosecutor’s name.
On Wednesday, when a reporter noted that Mr. Trump had accused Mr. Biden of “having him arrested, effectively directing his arrest,” Karine Jean-Pierre, the White House press secretary, said, “I’m not going to comment.”
Eddie Vale, a longtime Democratic strategist, said the White House position made sense, given the need to avoid even the hint that Mr. Biden was meddling in Mr. Trump’s case.
But he said members of outside Democratic groups would most likely begin coming to Mr. Biden’s defense if the attacks continued.
“This is such a charged and hot subject,” Mr. Vale said. “There’s nothing to be gained by weighing in. But I think as it goes on, you will have folks on the outer circle weighing in.”
Strategists for Mr. Trump promise that the attacks will continue.
Chris LaCivita, a senior campaign consultant for Mr. Trump, said on Wednesday that it was fair to assign responsibility for the investigation to Mr. Biden because the special counsel was appointed by Mr. Biden’s attorney general.
“There’s a thing called in government, the chain of command,” he said.
America First Legal, the pro-Trump group founded by Stephen Miller, the architect of the former president’s immigration agenda, sent out a fund-raising appeal on Wednesday morning, using the indictment as a rallying cry.
The theme has been echoed by Mr. Trump’s staunchest allies in Congress, who trained their ire on Mr. Biden even as they also railed against the Justice Department, the F.B.I., the “mainstream media” and Democrats generally.
Most of them, it seemed, were trying to goad Mr. Biden into a reaction.
“I, and every American who believes in the rule of law, stand with President Trump against this grave injustice,” tweeted Speaker Kevin McCarthy, the leading Republican in Congress.
Mr. Biden has so far focused on governing.
On Tuesday, the president met with Jens Stoltenberg, the secretary general of NATO, in the Oval Office. Later, he hosted a Juneteenth concert on the South Lawn of the White House, an event where it was easy to avoid the subject of Mr. Trump.
“To me, making Juneteenth a federal holiday wasn’t just a symbolic gesture,” Mr. Biden told the crowd in brief remarks. “It was a statement of fact for this country to acknowledge the original sin of slavery.”
But it is likely to get more difficult to refrain from wading into the Trump situation.
On Saturday, the president is scheduled to attend a political rally with union supporters in Philadelphia. It is the kind of event where he would be expected to draw the contrast between himself and his rivals.
Mr. Biden may be able to navigate that issue in the short term; Mr. Trump has a long way to go to win the Republican nomination.
But if he does become Mr. Biden’s opponent for the presidency again, the strategy of avoidance may eventually have to change.
As the first lady told donors at an event in California — referring to Mr. Trump’s four-year term in the White House: “We cannot go back to those dark days. And with your help, we won’t go back.”
