Age in focus as Biden faces Trump in first presidential debate

For 90 minutes on Thursday night, U.S. President Joe Biden has the chance to show doubting Americans that, at age 81, he is capable of handling the rigors of another four-year term, when he faces off in a debate against Republican Donald Trump.

A strong showing could help neutralize those concerns and focus voter attention on policy issues. A weak performance could dampen fundraising and push Trump further ahead in the polls.

Both men are under scrutiny over their age and stamina. Trump is 78 and prone to making outlandish statements and mangling his sentences on the campaign trail.

Biden has a stiff gait, makes verbal slip-ups and has inconsistent public appearances, sometimes veering from solidly delivered speeches to rushed, mumbled public remarks in the same day.

A recent Reuters-Ipsos poll showed that mental fitness is one of the key issues for undecided voters ahead of the Nov. 5 election, and they are more worried about Biden.