If anyone gets a thank-you note from President Biden for helping get him out of a jam in recent days, it should probably be former President Donald J. Trump.
Just when Mr. Biden was swamped by unwelcome questions about his age, his predecessor and challenger stepped in, rescuing him with an ill-timed diatribe vowing to “encourage” Russia to attack NATO allies that do not spend enough on their militaries.
The stunner from Mr. Trump over the weekend not only drew attention away from the president’s memory problems, as detailed in a special counsel report, but also provided a convenient way for Mr. Biden’s defenders to reframe the issue: Yes, they could now say, the incumbent may be an old man who sometimes forgets things, but his challenger is both aging and dangerously reckless.
It was not the first time, nor likely will it be the last, that Mr. Trump has stepped up when an adversary was in trouble to provide an escape route with an ill-considered howler of his own. Mr. Trump’s lifelong appetite for attention has often collided with his evident best interest. For Mr. Biden, that may be the key to this year’s campaign, banking on his opponent’s inability to stay silent at critical moments and hoping that he keeps reminding voters why they rejected him in 2020.
“There’s a saying that the enemy of your enemy is your friend,” said Alex Conant, a Republican strategist who worked on the 2016 presidential campaign of Senator Marco Rubio of Florida, who lost the party nomination that year to Mr. Trump. “Since Trump is his own worst enemy, he’s arguably Biden’s best friend.”
That does not mean that age is no longer a political liability for Mr. Biden, who at 81 is already the oldest president in American history and would be 86 at the end of a second term. While Mr. Trump is close behind him at 77, the special counsel’s characterization of the president as a “well-meaning, elderly man with a poor memory” proved searing and damaging.
A new poll by ABC News and Ipsos released on Sunday found that 86 percent of Americans think Mr. Biden is too old to serve another term as president, while 62 percent consider Mr. Trump too old.
But in Washington, the traditional political strategy when under fire is to change the subject as quickly as possible. Mr. Biden’s team set out to make the real issue not his own capacity but the conduct of the special counsel, Robert K. Hur, just as past presidents like Mr. Trump and Bill Clinton have sought to redirect attention from allegations against them to the prosecutors who investigated them.
White House surrogates and friends flooded the airwaves in the days afterward to assail Mr. Hur for citing the president’s inability to remember key dates, including the year of the death of his son Beau. In a fund-raising appeal, Jill Biden, the first lady, denounced Mr. Hur’s “inaccurate and personal political attacks about Joe,” then asked supporters for money. The pushback might not persuade voters already opposed to Mr. Biden, but it gave Democrats something else to talk about.
Mr. Trump played right into the Biden camp’s strategy during a rally in South Carolina on Saturday by castigating “delinquent” NATO members and saying that not only would he not come to their defense if attacked by the Russians, but he would also encourage the Russians “to do whatever the hell they want” against such allies.
“Donald Trump can’t help himself,” said Rodell Mollineau, a Democratic strategist and Partner at ROKK Solutions. “He will always try to turn the focus to him, even when it’s not in his advantage to do so. I expect many more hold-my-beer moments from Trump before this election is over.”
Nikki Haley, the former U.N. ambassador and South Carolina governor, who is still trying to wrest the Republican nomination away from the front-running Mr. Trump, seized on that penchant to bolster her case that the party should not trust him to lead it to victory this fall.
“That’s what you’re going to get, is unhinged chaos,” Ms. Haley said on Fox News. “And that only makes Joe Biden,” she added, “sound sane. When you get Donald Trump making Joe Biden sound sane, it’s more of the reason why Donald Trump can’t defeat Joe Biden. They’re taking everything he’s saying and they’re going to use it against him.”
Mr. Biden’s camp certainly sought to do just that. The White House released a statement saying that “encouraging invasions of our closest allies by murderous regimes is appalling and unhinged.” In a separate statement released by his campaign, Mr. Biden said Mr. Trump’s comments were “predictable coming from a man who is promising to rule as a dictator like the ones he praises on day one if he returns to the Oval Office.” On social media, he referred to Mr. Trump as one of the Russian president Vladimir V. Putin’s “useful lackeys.”
Robert Gibbs, a former White House press secretary to President Barack Obama, said the latest episode proved that Mr. Trump was incapable of heeding an old political adage: “If your opponent is having a bad day, simply get out of the way and let it happen.”
For Mr. Biden, he said, such out-of-the-blue opportunities may prove decisive. “The dexterity of the president and his team to drive those moments is going to be maybe one of the big determining factors as to who wins this race.”