A new national poll conducted in the wake of the Biden-Trump presidential debate has found that nearly 80% of voters are concerned about Biden "not having the necessary mental and physical health to be a president for a second term." 

The NBC News survey of 800 registered voters, which was conducted over July 7-9 and before the assassination attempt against former President Trump during a rally in Pennsylvania this past weekend, has Trump leading Biden by 45% to 43% in a head-to-head race. 

While the matchup remains close, the poll found that 62% of Democratic voters wish someone else was at the top of their party's ticket instead of Biden and that 79% of all voters are worried about the 81-year-old Biden’s mental and physical capabilities.

Only 50% of respondents had the same mental and physical fitness concerns about Trump, who is 78.

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Meanwhile, 58% indicated they had major or moderate concerns regarding Trump being found guilty by a jury in New York "on 34 felony counts of falsifying business records in a hush money case and Trump facing additional felony charges, including related to attempts to overturn the 2020 election." 

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As for the debate, 71% of respondents said it "made no difference" in terms of which candidate they support.  

President Biden’s widely criticized performance at the June 27 debate had shifted the trajectory of the race, with some congressional Democrats calling for him to step aside. 

In a potential head-to-head matchup with Vice President Kamala Harris – whose name has been floated as a potential replacement for Biden if he drops out of the race – Trump leads her 47% to 45%, according to the NBC poll.