Biden's biggest weakness -- his age -- on full display at debate: ANALYSIS

From the earliest moments of the night, President Joe Biden's biggest political weakness -- his age and perceived frailty -- became a clear liability on the debate stage Thursday. In a particularly low point for the president, Biden seemingly lost his train of thought while responding to a question about the national debt, pausing and trailing off into a comment about finally "beat[ing] Medicare." Donald Trump jumped on this flub when the CNN moderators turned to him, quipping that Biden had "beat Medicare to death."

While Biden, 81, gained steam as the debate went on, and was clearly well-prepared to respond to both the questions and Trump's claims on the stage -- backing up his answers with stats and fact-checking the former president on the spot -- his hoarse voice and quiet demeanor (which his campaign chalked up to a previously undisclosed cold) play into the concerns many Americans have about his age.

Though Trump is also no spring chicken at 78, he appeared much more lively and spry on the debate stage, and voters typically report feeling less concerned about his age. To wit: in a poll from The New York Times and Siena College from June 20 to 25, just 16% of registered voters said that Trump's age "is such a problem that he is not capable of handling the job of president," while a whopping 45% said the same about Biden, including 15% of Democrats.

Trump, meanwhile, began the night with a calmer demeanor than we've seen from him in the past, and he was largely respectful of the debate rules around time limits and interruptions. Though he didn't shy away from Trumpy turns of phrase or well-worn spin, his clear but calm speaking style was in stark contrast to Biden's rasp.

Trump did his best to tackle one of his biggest weaknesses: an unpopular Republican party position on abortion. When asked about the Supreme Court's overturning of Roe v. Wade two years ago, Trump said that the three justices he appointed who decided the Dobbs case "just so happened" to vote against existing precedent. He took the more moderate conservative stance that abortion policy should be left up to the states -- which Biden countered would open the door for further rollback of reproductive rights. Trump repeated false claims that Democratic leaders systematically favor late-term abortions and "aborting" babies after they are born.

(Trump claimed that Democrats "support abortion up to and even beyond the ninth month," and contended that some Democratic states have had such a stance. Democrats have never advocated for killing a baby after it is born as this would be murder, which is illegal in every state.)

A Washington Post/George Mason University Schar School poll of young swing-state "deciding" voters published this week found that 38% of adults said they thought Biden would to a better job of handling abortion, versus 31% who said they thought Trump would do a better job.

But monitoring of live voter responses to the debate (something campaigns call "the dials," since live respondents get to pick whether they think a candidate is doing well or poorly) showed Trump doing poorly when he attacked Biden too aggressively. That was also a liability for him in the first debate in 2020, after which polls moved toward Biden by 2.6 percentage points. That may cap his upside from Thursday's debate.

Overall, the substance of Biden's responses outpaced his style. He attacked Trump for previous comments he had made about there being "very fine people on both sides" of the deadly Unite the Right rally in Charlottesville, Virginia, in 2017; for his role in organizing the rally that preceded the deadly attack on the U.S. Capitol on Jan. 6, 2021, and for his efforts to overturn the 2020 election. He also noted Trump's recent felony conviction, another political weakness for the former president. But his delivery lacked the energy we've come to expect from Biden on a debate stage, and made many of these solid attacks fall flat.

Ultimately, Biden won the debate on policy but lost it on presentation, and failed to reassure voters he is up for another four years.