In the wake of a special counsel report that characterized President Biden as a “well-meaning elderly man with a poor memory,” Republicans are focusing their fire on what may be Mr. Biden’s greatest vulnerability: his age. 

In his report on documents found at Mr. Biden’s home, Special Counsel Robert Hur, who was called out of retirement by Attorney General Garland to conduct the investigation, found that there was “insufficient evidence” to “establish Mr. Biden’s guilt beyond a reasonable doubt.”

Yet Mr. Hur took a kill shot at the president’s cognition and mental acuity, writing that a jury would be unlikely to convict Mr. Biden of criminal wrongdoing — even if he did have enough evidence to bring charges — because Mr. Biden would be perceived as a “sympathetic, well-meaning elderly man with a poor memory.”

In response to the report, Mr. Biden scheduled an emergency press conference on Thursday evening, during which he rebuked the special counsel’s characterization and fired back at reporters asking about his age. 

“I’m well-meaning, and I’m an elderly man, and I know what the hell I’m doing,” Mr. Biden told reporters. “I’ve been president, and I put this country back on its feet. I don’t need his recommendation.”

Mr. Biden did not help his case when, during this press appearance, he referred to the president of Egypt, Abdel Fattah El-Sisi, as the “president of Mexico.”

Since its release, Republicans have rushed to make hay out of the report, with Speaker Johnson leading the way, saying in a joint statement with other House GOP leaders: “A man too incapable of being held accountable for mishandling classified information is certainly unfit for the Oval Office.”

“The President’s press conference this evening further confirmed on live television what the special counsel report outlined. He is not fit to be president,” Mr. Johnson added in a post on social media.

Congresswoman Claudia Tenney, in an interview with Fox News, said, “If he can’t stand trial he certainly can’t carry out the duties of the president of the United States.”

“A President with diminished mental capacity is a serious, alarming situation,” Congressman Ralph Norman said in a post. “We’re long past the point where this can be blissfully ignored.”

Mr. Norman added: “This is a complete disaster, and Biden’s press conference tonight did him no favors.”

Republican members of the Senate also had harsh words for Mr. Biden in the wake of the special counsel’s report, including Senator Tillis, who posted: “Is this a joke?”

Senator Lee, regarding Mr. Biden’s error about Mr. Al Sisi, rhetorically asked the president: “Will you be serving him Egyptian tacos for lunch?”

Other senators complained about a “two-tiered” justice system in America, claiming it is unreasonable that there were charges brought against President Trump over his mishandling of classified material, but not Mr. Biden. 

“A lot of Republicans will think there’s a double standard,” Senator Graham told reporters. “The American people will make a decision on whether he’s up to another term based on things like this.” 

Senator Blackburn also made this point, saying, “Tennesseans and Americans are fed up with the two tiers of justice that has become the status quo of this administration.”

“President Biden mishandled classified documents for years, storing them in the garage of his Delaware home, and yet, no charges are expected,” Ms. Blackburn said.

Mr. Trump, who has often made this claim in the past, released a slew of posts on Truth Social Thursday night and Friday morning referencing an alleged “two-tiered” justice system, saying in a post: “VERY UNFAIR. THIS NONSENSE MUST END.”

Mr. Biden on Thursday night insisted there were clear differences between his case and that of Mr. Trump, and that Mr. Hur had found he did not break the law.

In the special counsel’s report, he did note “several material distinctions” between Mr. Trump’s case and Mr. Biden’s case, including that Mr. Trump, according to the report, allegedly “not only refused to return the documents for many months, but he also obstructed justice by enlisting others to destroy evidence and then to lie about it.”

Republicans such as Lieutenant Governor Dan Patrick of Texas strayed into speculation about what this report might mean for the 2024 presidential election.

“I’ve said for over a year many times that Joe Biden would not be on the ticket and Michelle Obama would be the likely nominee,” Mr. Patrick said in a post. “It’s clear the Democrat deep state run by Barack Obama knew they had to take him down to give them a chance in November.”

Mr. Patrick explained: “They set him up in the report calling him a ‘sympathetic, well-meaning, elderly man with a poor memory’” and “protected him by putting him in the Oval Office.”

“He doesn’t have a memory and Kamala doesn’t have a brain. Now they have a real problem,” Mr. Patrick concluded.