(NewsNation) — As President Joe Biden and former President Donald Trump appear to be headed for a rematch at the polls, age has become a topic of conversation for voters.

Both candidates are over the age of 75. Trump would be 78 when sworn in if he won a second term, while Biden, now 81, would be 82 at his inauguration.

Despite the small age gap, polls show voters are significantly more concerned about Biden’s age. The Biden-Harris campaign has said the president has no intention of dropping out. But does the party have a Plan B?

At this point, it’s nearly impossible for the Democrats to pick a different nominee. Plus, Biden has said himself he isn’t going anywhere, so it’s unlikely he would bow out.

The White House has been packing the president’s schedule as criticism grows around his physical and mental fitness. Earlier on Monday, he spoke with a group of county elected officials visiting Washington, D.C., and later, he will welcome the King of Jordan as work continues on a hostage deal between Israel and Hamas.

But people are still watching his every move, with some questioning why the Democratic National Committee isn’t choosing another nominee. But at this point, the deadlines have passed for names to appear on the ballot, making a change difficult.

Biden does have some things on his side, including name recognition, cash on hand for his campaign along with a campaign operation already in place. He also has the experience that comes with his age.

At this point, the only way for the Democrats to get a new nominee would fall to the delegates already pledged to Biden. If Biden were to drop out after the convention, there would have to be a special meeting to choose a new nominee, something that could get messy and political.

If Biden drops out, the nomination doesn’t automatically go to Vice President Kamala Harris. She is only in the line of succession if he gives up his presidency, not the nomination. She would have to win delegates over on her own.

Harris says she is ready to serve. First lady Jill Biden is also standing by her husband’s side, getting involved in the conversation about Biden’s memory by sending an email to donors about the president’s memory of his son Beau’s death and whether the special counsel’s report was meant to “score political points.”