WASHINGTON — President Joe Biden’s age and former President Donald Trump’s legal troubles may be casting doubts among voters on whether the two candidates will end up as their party’s nominee, according to a new Monmouth University poll released Thursday.

The poll, conducted between Feb. 8 and Feb. 12, found that 48% of voters think it is very or somewhat likely that Biden will be replaced as the Democratic nominee. By comparison, the poll found that 32% of voters think it is very or somewhat likely that Trump will be replaced as the Republican nominee.

The voters that think Biden will be replaced generally cited concerns about his age, physical health and mental stamina as reasons for why.

Questions around Biden’s age and acuity have only increased after special counsel Robert Hur released a scathing report that portrayed the president as a “well-meaning elderly man with a poor memory.”

“The Hur report doesn’t seem to have shifted public opinion on whether Biden mishandled classified documents. At the same time, it probably has done more to reinforce existing views of Biden’s physical and mental vigor. When we asked a different question about each candidate’s age back in the fall, there was already a wide gap in concern about Biden compared with Trump,” Patrick Murray, director of the Monmouth University Polling Institute, said in a news release.

Most voters who think Trump will be replaced cited his legal troubles while a few mentioned his health.

Trump currently faces 91 felony charges across four indictments for his alleged efforts in trying to overturn the 2020 election, mishandling classified documents and falsifying business records. He also faces numerous civil lawsuits.

But overall, 51% of voters are atleast somewhat confident that Trump has the physical and mental stamina to carry out presidential duties while only 32% are confident about Biden. This marks a difference from 2020, where 45% were confident in Trump’s stamina and 52% were confident in Biden’s stamina, according to the Monmouth University news release.

The poll was conducted with 902 adults, with the results of the poll based on a subsample of 822 registered voters. It has a margin of error of plus or minus 4.3 percentage points.

This article originally appeared on USA TODAY: Nearly half of voters think Biden could be replaced as Democratic nominee, new poll finds